13 graphs of log and exp functions

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Graphs of Log and Exponential Functions

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Page 1: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

Page 2: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

Page 3: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Graphs of Log and Exponential Functions

exx

Page 4: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Graphs of Log and Exponential Functions

exx

We gather the following information:

Page 5: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.

Page 6: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.* The x intercept and y intercept

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Page 7: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.* The x intercept and y intercept* The behavior as x ±∞ and as x v-asymptotes

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Page 8: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.* The x intercept and y intercept

* The critical points where f ' = 0 or f ' is not defined* The behavior as x ±∞ and as x v-asymptotes

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Page 9: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.* The x intercept and y intercept

* The critical points where f ' = 0 or f ' is not defined* The inflection points

* The behavior as x ±∞ and as x v-asymptotes

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Page 10: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.* The x intercept and y intercept

* The critical points where f ' = 0 or f ' is not defined* The inflection points

Domain: All real numbers

* The behavior as x ±∞ and as x v-asymptotes

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Page 11: 13 graphs of log and exp functions

In this section we examine the graphs of functions related to log and exponential functions.

Graphs of Log and Exponential Functions

exx

We gather the following information:

* The domain, find the vertical asymptotes, if any.* The x intercept and y intercept

* The critical points where f ' = 0 or f ' is not defined* The inflection points

Domain: All real numbers

* The behavior as x ±∞ and as x v-asymptotes

x intercept and y intercept: (0, 0)

Example: Sketch the graph y = . Find the criticalpoints and the inflection points, if any.

Page 12: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

The behavior as x ±∞:

Page 13: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The behavior as x ±∞:

x∞

Page 14: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞

Page 15: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Page 16: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞

Page 17: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞0+

Page 18: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

Page 19: 13 graphs of log and exp functions

Graphs of Log and Exponential FunctionsDomain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

x

y

Page 20: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

x

y

Page 21: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

x

y

Page 22: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

x

y

Page 23: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

y

Page 24: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

Page 25: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

=

Page 26: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

=

Page 27: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 =

Page 28: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1,= and y=1/e.

Page 29: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

For the inflection point:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1. = and y=1/e.

Page 30: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1. =

f " = -e-x(1 – x) – e-x

and y=1/e.For the inflection point:

Page 31: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1. =

f " = -e-x(1 – x) – e-x = -2e-x + xe-x

and y=1/e.For the inflection point:

Page 32: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1. =

f " = -e-x(1 – x) – e-x = -2e-x + xe-x

= e-x(2 – x)

and y=1/e.For the inflection point:

Page 33: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1. =

f " = -e-x(1 – x) – e-x = -2e-x + xe-x

= e-x(2 – x) = 0 x = 2 and y = 2/e2.

and y=1/e.For the inflection point:

Page 34: 13 graphs of log and exp functions

Lim

Graphs of Log and Exponential Functions

exx

The critical points where f ' = 0 or f ' is not defined:

The behavior as x ±∞:

x∞=

L'Hopital's Rule

Lim ex1

x∞= 0+

Lim exx

x-∞= -∞

0+

f ' = e2xex – xex

e2xex(1 – x)

= e-x(1 – x) = 0 when x = 1. =

Put all this information together:

f " = -e-x(1 – x) – e-x = -2e-x + xe-x

= e-x(2 – x) = 0 x = 2 and y = 2/e2.

and y=1/e.For the inflection point:

Page 35: 13 graphs of log and exp functions

Graphs of Log and Exponential FunctionsDomain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

x

y

Page 36: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

x

y

Page 37: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

x

y

Page 38: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

x

y

Page 39: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

(1, 1/e) critical point

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

x

y

Page 40: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

(1, 1/e) critical point

(2, 2/e2 ) inflection point

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

x

y

Page 41: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

(1, 1/e) critical point

(2, 2/e2 ) inflection point

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

(2, 2/e2 ) inflection point

x

y

Page 42: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

x-int. and y-int.: (0, 0)

y 0+ as x ∞

y -∞ as x -∞

(1, 1/e) critical point

(2, 2/e2 ) inflection point

Domain: All real numbersx intercept and y intercept: (0, 0)as x +∞, y 0+ as x –∞, y –∞,

(1, 1/e) critical point

(2, 2/e2 ) inflection point

x

y

Page 43: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

-x2

Page 44: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

-x2

Page 45: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept:

-x2

Page 46: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1),

-x2

Page 47: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

Page 48: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞:

Page 49: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e

x∞

-x2 -x2

x- ∞

Page 50: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

Page 51: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points:

Page 52: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: f ' = -2xe = 0 -x2

Page 53: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: -x2

f ' = -2xe = 0 x = 0 and y = 1

Page 54: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: -x2

The inflection points:

f ' = -2xe = 0 x = 0 and y = 1

Page 55: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: -x2

The inflection points: f " = -2e + 4x2e -x2 -x2

f ' = -2xe = 0 x = 0 and y = 1

Page 56: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: -x2

The inflection points: f " = -2e + 4x2e = -2e (1 – 2x2)-x2 -x2 -x2

f ' = -2xe = 0 x = 0 and y = 1

Page 57: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: f ' = -2xe = 0 x = 0 and y = 1 -x2

The inflection points: f " = -2e + 4x2e = -2e (1 – 2x2)-x2 -x2 -x2

1 – 2x2 = 0

Page 58: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: -x2

The inflection points: f " = -2e + 4x2e = -2e (1 – 2x2)-x2 -x2 -x2

1 – 2x2 = 0 x = ±1/2

f ' = -2xe = 0 x = 0 and y = 1

Page 59: 13 graphs of log and exp functions

Example: Sketch the graph y = e .

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: All real numbers

x intercept and y intercept: y-int: (0, 1), there is no x-int. (e = 0)

-x2

-x2

The behavior as x ±∞: Lim e = lim e = 0+

x∞

-x2 -x2

x- ∞

The critical points: -x2

The inflection points: f " = -2e + 4x2e = -2e (1 – 2x2)-x2 -x2 -x2

1 – 2x2 = 0 x = ±1/2 and y = 1/e

f ' = -2xe = 0 x = 0 and y = 1

Page 60: 13 graphs of log and exp functions

Graphs of Log and Exponential FunctionsDomain: All real numbersy-int: (0, 1), there is no x-int.

(±1/2,1/ e ) are inflection points

as x ± ∞, y 0+ (0, 1) critical point

x

y

Page 61: 13 graphs of log and exp functions

Graphs of Log and Exponential FunctionsDomain: All real numbersy-int: (0, 1), there is no x-int.

(±1/2,1/ e ) are inflection points

as x ± ∞, y 0+ (0, 1) critical point

y-int: (0, 1), critical pt.

x

y

Page 62: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

y 0+ as x ∞y 0+ as x -∞

Domain: All real numbersy-int: (0, 1), there is no x-int.

(±1/2,1/ e ) are inflection points

as x ± ∞, y 0+ (0, 1) critical point

y-int: (0, 1), critical pt.

x

y

Page 63: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

y 0+ as x ∞y 0+ as x -∞

(1/2, e-1/2 ) inf. pt(-1/2, e-1/2 ) inf. pt

y-int: (0, 1), critical pt.

Domain: All real numbersy-int: (0, 1), there is no x-int.

(±1/2,1/ e ) are inflection points

as x ± ∞, y 0+ (0, 1) critical point

x

y

Page 64: 13 graphs of log and exp functions

Graphs of Log and Exponential Functions

y 0+ as x ∞y 0+ as x -∞

(1/2, e-1/2 ) inf. pt(-1/2, e-1/2 ) inf. pt

y-int: (0, 1), critical pt.

Domain: All real numbersy-int: (0, 1), there is no x-int.

(±1/2,1/ e ) are inflection points

as x ± ∞, y 0+ (0, 1) critical point

x

y

Page 65: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Page 66: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

Page 67: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int.

Page 68: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0

Page 69: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

Page 70: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞:

Page 71: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x

x∞

Page 72: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x = lim 1/x

x∞ x∞

L'Hopital's Rule

Page 73: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x = lim 1/x = 0

x∞ x∞

L'Hopital's Rule

Page 74: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x = lim 1/x = 0

x∞ x∞

L'Hopital's Rule

The behavior as x 0+:

Page 75: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x = lim 1/x = 0

x∞ x∞

L'Hopital's Rule

The behavior as x 0+: Lim Ln(x)/x x0+

Page 76: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x = lim 1/x = 0

x∞ x∞

L'Hopital's Rule

The behavior as x 0+: Lim Ln(x)/xx0+

-∞

0+

Page 77: 13 graphs of log and exp functions

Example: Sketch the graph y = Ln(x)/x.

Find the critical points and the inflection points, if any.

Graphs of Log and Exponential Functions

Domain: x > 0

x intercept and y intercept: No y-int. For x-int: Ln(x) = 0 x = 1, so (1, 0) is the x-int.

The behavior as x ∞: Lim Ln(x)/x = lim 1/x = 0

x∞ x∞

L'Hopital's Rule

The behavior as x 0+: Lim Ln(x)/x = -∞x0+

-∞

0+

Page 78: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

Page 79: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0

Page 80: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e, , and y=1/e.

Page 81: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3)

and y=1/e.

Page 82: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

and y=1/e.

Page 83: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

So -3 + 2Ln(x) = 0

and y=1/e.

Page 84: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

So -3 + 2Ln(x) = 0 Ln(x) = 3/2 or x = e3/2,

and y=1/e.

and y=(3/2)/e3/2 .

Page 85: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

So -3 + 2Ln(x) = 0 Ln(x) = 3/2 or x = e3/2,

x-int: (1, 0)

and y=1/e.

and y=(3/2)/e3/2 .

x

y

Page 86: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

y 0+ as x ∞

x-int: (1, 0)

y - ∞ as x 0+

and y=1/e.

and y=(3/2)/e3/2 .So -3 + 2Ln(x) = 0 Ln(x) = 3/2 or x = e3/2,

x

y

Page 87: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

y 0+ as x ∞

(e, 1/e) critical pt.

x-int: (1, 0)

y - ∞ as x 0+

and y=1/e.

and y=(3/2)/e3/2 .So -3 + 2Ln(x) = 0 Ln(x) = 3/2 or x = e3/2,

x

y

Page 88: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

y 0+ as x ∞

(e, 1/e) critical pt.

x-int: (1, 0)

y - ∞ as x 0+

(3/2, 3e-3/2/2 ) inf. pt

and y=1/e.

and y=(3/2)/e3/2 .So -3 + 2Ln(x) = 0 Ln(x) = 3/2 or x = e3/2,

x

y

Page 89: 13 graphs of log and exp functions

The critical pt:

Graphs of Log and Exponential Functions

f ' = 1/x2 – Ln(x)/x2 = 0 1 – Ln(x) = 0 or x = e,

The inflection pt:

f " = -2/x3 – (1/x3 – 2Ln(x)/x3) = -3/x3 + 2Ln(x)/x3 = 0

y 0+ as x ∞

(e, 1/e) critical pt.

x-int: (1, 0)

y - ∞ as x 0+

(3/2, 3e-3/2/2 ) inf. pt

and y=1/e.

and y=(3/2)/e3/2 .

Graph y = x2e-2x

Graph y = x2Ln(x)

Your Turn:

So -3 + 2Ln(x) = 0 Ln(x) = 3/2 or x = e3/2,

x

y