antiderivatives and indefinite integration lesson 5.1
TRANSCRIPT
Antiderivatives and Indefinite Integration
Lesson 5.1
Reversing Differentiation
• An antiderivative of function f is • a ________________F• which satisfies __________
• Consider the following:
• We note that two antiderivatives of the same function differ by a __________________
4
3
( ) 2
'( ) 8
F x x
F x x
4
3
( ) 2 17
'( ) 8
G x x
G x x
Reversing Differentiation
• General antiderivativesf(x) = 6x2 F(x) = 2x3 + C• because ___________ = 6x2
k(x) = sec2(x) K(x) = ___________________• because K’(x) = k(x)
Differential Equation
• A differential equation in x and y involves• x, y, and _____________________ of y
• Examples
• Solution – find a function whose ___________is the differential given
3
' 5
' 4
y x
y x
Differential Equation
• When
• Then one such function is
• The general solution is
' 5y x
25
2y x
Notation for Antiderivatives
• We are starting with
• Change to differential form
• Then the notation for antiderivatives is
( )dy
f xdx
( ) ( )y f x dx F x C "The ______________of f with respect to x"
Basic Integration Rules
• Note the inverse nature of integration and differentiation
• Note basic rules, pg 286
'( ) ( )F x dx F x C
Practice
• Try these3 24 6 1x x dx
2
4
2 3x xdx
x
sec tan secy y y dy
Finding a Particular Solution
• Given
• Find the specific equation from the family of antiderivatives, whichcontains the point (3,2)
• Hint: find the __________________, use the given point to find the value for C
2 1dy
xdx
Assignment A
• Lesson 5.1 A• Page 291• Exercises 1 – 55 odd
Slope Fields
• Slope of a function f(x)• at a point a• given by f ‘(a)
• Suppose we know f ‘(x)• substitute different values for a • draw short slope lines for successive values of y
• Example
'( ) 2f x x
Slope Fields
• For a large portion of the graph, when
• We can trace the line for a specific F(x)• specifically when the C = -3
'( ) 2f x x
Finding an Antiderivative Using a Slope Field
• Given
• We can trace the version of the original F(x) which _______________________.
2
'( ) xf x e
Vertical Motion
• Consider the fact that the acceleration due to gravity a(t) = -32 fps
• Then v(t) = -32t + v0 • Also s(t) = -16t2 + v0t + s0
• A balloon, rising vertically with velocity = 8 releases a sandbag at the instant it is 64 feet above the ground• How long until the sandbag hits the ground• What is its velocity when this happens?
Why?Why?
Rectilinear Motion
• A particle, initially at rest, moves along the x-axis at velocity of
• At time t = 0, its position is x = 3• Find the velocity and position functions for the
particle• Find all values of t for which the particle is at rest
( ) cos 0a t t t
Assignment B
• Lesson 5.1 B• Page 292• Exercises 57 – 93, EOO
Area as the Limit of a SumLesson 5.2
Area under f(x) = ln x
• Consider the task to compute the area under a curve f(x) = ln x on interval [1,5]
1 2 3 4 5
x
We estimate with 4 rectangles using the _________endpoints
Area under the Curve
1 2 3 4 5
x
4 ln 2 ln 3 ln 4 ln 5S x x x x
We can ________________our estimate by increasing the number of rectangles
Area under the Curve• Increasing the number of rectangles to n
• This can be done on the calculator:
5 1 4b ax
n n n
4 1 2 3ln ln ln ... ln nS x x x x x x x x
Generalizing
• In general …
• The actual area is
• where
a b
( ) ... ( )nS f a x x f a n x x
_______ ( ) ... ( )f a x x f a n x x
Summation Notation
• We use summation notation
• Note the basic rules and formulas• Examples pg. 295• Theorem 5.2 Formulas, pg 296
1 21
...n
n kk
a a a a
Use of Calculator
• Note again summation capability of calculator• Syntax is:
(expression, variable, low, high)
Practice Summation
• Try these
50
1
3k
5
1
( 1)k
k
402
1
( 1)k
k
Practice Summation
• For our general formula:
• let f(x) = 3 – 2x on [0,1]
Assignment
• Lesson 5.2• Page 303• Exercises 1 – 61 EOO
(omit 45)
Riemann Sums and the Definite Integral
Lesson 5.3
Review
• We partition the interval into n ____________
• Evaluate f(x) at _________endpointsof kth sub-interval for k = 1, 2, 3, … n
a b
f(x)
b ax
n
Review
• Sum
• We expect Sn to improve thus we define A, the ______________under the curve, to equal the above limit.
a b
1
lim ( )n
nn
k
S f a k x x
f(x)
Riemann Sum
1. Partition the interval [a,b] into n subintervalsa = x0 < x1 … < xn-1< xn = b
• Call this partition P• The kth subinterval is xk = xk-1 – xk
• Largest xk is called the _________, called ||P||
2. Choose an arbitrary value from each
subinterval, call it _________
Riemann Sum3. Form the sum
This is the Riemann sum associated with• the function ______• the given partition ____• the chosen subinterval representatives ______
• We will express a variety of quantities in terms of the Riemann sum
1 1 2 21
( ) ( ) ... ( ) ( )n
n n n i ii
R f c x f c x f c x f c x
1 1 2 21
( ) ( ) ... ( ) ( )n
n n n i ii
R f c x f c x f c x f c x
The Riemann SumCalculated
• Consider the function2x2 – 7x + 5
• Use x = 0.1
• Let the = left edgeof each subinterval
• Note the sum
x 2x 2̂-7x+5 dx * f(x)4 9 0.9
4.1 9.92 0.9924.2 10.88 1.0884.3 11.88 1.1884.4 12.92 1.2924.5 14 1.44.6 15.12 1.5124.7 16.28 1.6284.8 17.48 1.7484.9 18.72 1.872
5 20 25.1 21.32 2.1325.2 22.68 2.2685.3 24.08 2.4085.4 25.52 2.5525.5 27 2.75.6 28.52 2.8525.7 30.08 3.0085.8 31.68 3.1685.9 33.32 3.332
Riemann sum = 40.04
x 2x 2̂-7x+5 dx * f(x)4 9 0.9
4.1 9.92 0.9924.2 10.88 1.0884.3 11.88 1.1884.4 12.92 1.2924.5 14 1.44.6 15.12 1.5124.7 16.28 1.6284.8 17.48 1.7484.9 18.72 1.872
5 20 25.1 21.32 2.1325.2 22.68 2.2685.3 24.08 2.4085.4 25.52 2.5525.5 27 2.75.6 28.52 2.8525.7 30.08 3.0085.8 31.68 3.1685.9 33.32 3.332
Riemann sum = 40.04
ic
The Riemann Sum
• We have summed a series of boxes• If the x were ____________________, we
would have gotten a better approximation
f(x) = 2x2 – 7x + 5
1
( ) 40.04n
i ii
f c x
The Definite Integral
• The definite integral is the _______of the Riemann sum
• We say that f is _____________ when• the number I can be approximated as accurate as
needed by making ||P|| sufficiently small• f must exist on [a,b] and the Riemann sum must
exist
0
1
( ) limnb
i ia Pk
I f x dx f c x
Example
• Try
• Use summation on calculator.
3 4
24
11
use (1 )k
x dx S f k x x
b ax
n
Example
• Note increased accuracy with __________ x
Limit of the Riemann Sum
• The definite integral is the ___________of the Riemann sum.
3
2
1
x dx
Properties of Definite Integral
• Integral of a sum = sum of integrals• Factor out a _________________• Dominance
( ) ( ) [ , ]
( ) ( )b b
a a
f x g x on a b
f x dx g x dx
Properties of Definite Integral
• Subdivision rule
( ) ( ) ____________c b
a a
f x dx f x dx
a b c
f(x)
Area As An Integral
• The area under the curve on theinterval [a,b] a c
f(x)
A
Distance As An Integral
• Given that v(t) = the velocity function with respect to time:
• Then _____________________ can be determined by a definite integral
• Think of a summation for many small time slices of distance
( )t b
t a
D v t dt
Assignment
• Section 5.3• Page 314• Problems: 3 – 49 odd
The Fundamental Theorems of Calculus
Lesson 5.4
First Fundamental Theorem of Calculus
• Given f is • _________________on interval [a, b]• F is any function that satisfies F’(x) = f(x)
• Then
( ) __________________b
af x dx
First Fundamental Theorem of Calculus
• The definite integral
can be computed by• finding an _________________F on interval [a,b]• evaluating at limits a and b and _____________
• Try
( )b
af x dx
7
36x dx
Area Under a Curve
• Consider
• Area =
sin cos on 0,2
y x x
Area Under a Curve
• Find the area under the following function on the interval [1, 4]
2( 1)y x x x
Second Fundamental Theorem of Calculus
• Often useful to think of the following form
• We can consider this to be a _______________ in terms of x
( )x
af t dt
( ) ( )x
aF x f t dt View QuickTime
Movie
View QuickTime Movie
Second Fundamental Theorem of Calculus• Suppose we are
given G(x)
• What is G’(x)?
4( ) (3 5)
xG x t dt
Second Fundamental Theorem of Calculus
• Note that
• Then
• What about ?
( ) ( )
( ) ( )
x
aF x f t dt
F x F a
( ) ( )a
xF x f t dt
Since this is a _____________
Since this is a _____________
Second Fundamental Theorem of Calculus• Try this 1
2( )
1 3x
dtF x dt
t
( ) ( )
( ) ( )
so
a
xF x f t dt
F a F x
Assignment
• Lesson 5.4• Page 327• Exercises 1 – 49 odd
Integration by SubstitutionLesson 5.5
Substitution with Indefinite Integration
• This is the “backwards” version of the _____________________
• Recall …
• Then …
5 42 24 7 5 4 7 2 4dx x x x x
dx
4 52 25 4 7 2 4 4 7x x x dx x x C
Substitution with Indefinite Integration
• In general we look at the f(x) and “split” it• into a ________________________
• So that …
( )f x dx
( ) ( )du
f x g udx
( ) ( )du
g u dx G u Cdx
Substitution with Indefinite Integration
• Note the parts of the integral from our example
( ) ( )du
g u dx G u Cdx
4 52 25 4 7 2 4 4 7x x x dx x x C
Example
• Try this … • what is the g(u)?• what is the du/dx?
• We have a problem …
2(4 5)x dx
Where is the 4 which we need?Where is the 4 which we need?
Example
• We can use one of the properties of integrals
• We will insert a factor of _____inside and a factor of ¼ __________to balance the result
2)44
(41
5x dx
( ) ( )c f x dx c f x dx
Can You Tell?
• Which one needs substitution for integration?
• Go ahead and do the integration.
2
52
3 5
3 5
x x dx
x x dx
Try Another …
3 1t dt3sin cosx x dx
Assignment A
• Lesson 5.5• Page 340• Problems:
1 – 33 EOO49 – 77 EOO
Change of Variables
• We completely rewrite the integral in terms of u and du
• Example:
• So u = _________ and du = _________• But we have an x in the integrand
• So we solve for x in terms of u
2 3x x dx
3
2
ux
Change of Variables
• We end up with
• It remains to distribute the and proceed with the integration
• Do not forget to "_________________"
2 3 ________________x x dx 1
2u
What About Definite Integrals
• Consider a variationof integral from previous slide
• One option is to change the limits• u = __________ Then when t = 1, u = ___
when t = 2, u = ____• Resulting integral
2
1
3 1t dt
What About Definite Integrals
• Also possible to "un-substitute" and use the ___________________ limits
21 3 3
2 2 2
1
1 1 2 23 1
3 3 3 9u du u t
Integration of Even & Odd Functions
• Recall that for an even function• The function is symmetric about the ________
• Thus
• An odd function has• The function is symmetric about the orgin
• Thus
( ) ( )f x f x
0
( ) 2 ( )a a
a
f x dx f x dx
( ) _______a
a
f x dx
Assignment B
• Lesson 5.5• Page 341• Problems:
87 - 109 EOO117 – 132 EOO
Numerical Integration
Lesson 5.6
Trapezoidal Rule
• Instead of calculatingapproximation rectangleswe will use trapezoids• More accuracy
• Area of a trapezoid
a bx
•ix
b1
b2
h____________A
• Which dimension is the h?
• Which is the b1 and the b2
• Which dimension is the h?
• Which is the b1 and the b2
Trapezoidal Rule
• Trapezoidal rule approximates the integral
• Calculator function for f(x)((2*f(a+k*(b-a)/n),k,1,n-1)+f(a)+f(b))*(b-a)/(n*2)trap(a,b,n)
dx
f(xi)f(xi-1)
0 1 2 1( ) ( ) 2 ( ) 2 ( ) ...2 ( ) ( )2
where ____________
b
n n
a
dxf x dx f x f x f x f x f x
dx
Trapezoidal Rule• Entering the trapezoidal rule into the
calculator
• __________ must be defined for this to work
Trapezoidal Rule
• Try using the trapezoidal rule
• Check with integration
25
0
2 8x dx n
Simpson's Rule• As before, we divide
the interval into n parts• n must be ___________
• Instead of straight lines wedraw _____________through each group of three consecutive points• This approximates the original curve for finding
definite integral – formula shown below
a b•ix
0 1 2 3 4
2 1
( ) [ ( ) 4 ( ) 2 ( ) 4 ( ) 2 ( )3
... 2 ( ) 4 ( ) ( )]
b
a
n n n
dxf x dx f x f x f x f x f x
f x f x f x
Simpson's Rule
• Our calculator can do this for us also• The function is more than a one liner
• We will use the program editor• Choose APPS,
7:Program Editor3:New
• Specify Function,name it simp
Simpson's Rule
• Enter the parameters a, b, and n between the parentheses
Enter commands shown between Func and endFunc
Simpson's Rule
• Specify a function for ______________• When you call simp(a,b,n),
• Make sure n is an number
• Note the accuracy of the approximation
Assignment A
• Lesson 5.6• Page 350• Exercises 1 – 23 odd
Error Estimation
• Trapezoidal error for f on [a, b]• Where M = _______________of |f ''(x)| on [a, b]
• Simpson's errorfor f on [a, b]• Where K = max value of ___________ on [a, b]
3
212n
b aE M
n
5
4180n
b aE K
n
Using Data
• Given table of data, use trapezoidal rule to determine area under the curve
• dx = ?
x 2.00 2.10 2.20 2.30 2.40 2.50 2.60
y 4.32 4.57 5.14 5.78 6.84 6.62 6.51
0 1 2 1( ) ( ) 2 ( ) 2 ( ) ...2 ( ) ( )2
b
n n
a
dxf x dx f x f x f x f x f x
Using Data
• Given table of data, use Simpson's rule to determine area under the curve
0 1 2 3 4
2 1
( ) [ ( ) 4 ( ) 2 ( ) 4 ( ) 2 ( )3
... 2 ( ) 4 ( ) ( )]
b
a
n n n
dxf x dx f x f x f x f x f x
f x f x f x
x 2.00 2.10 2.20 2.30 2.40 2.50 2.60
y 4.32 4.57 5.14 5.78 6.84 6.62 6.51
Assignment B
• Lesson 5.6• Page 350• Exercises 27 – 39 odd
49, 51, 53
The Natural Log Function: Integration
Lesson 5.7
Log Rule for Integration
• Because
• Then we know that
• And in general, when u is a differentiable function in x:
1ln( )
dx
dx x
1dxx
Try It Out
• Consider these . . .
2
33
xdx
x
2sec
tan
xdx
x
Finding Area
• Given
• Determine the area under the curve on the interval [2, 4]
2
lny
x x
Using Long Division Before Integrating
• Use of the log rule is often in disguised form
• Do the division on this integrand and alter it's appearance
22 7 3
2
x xdx
x
22 2 7 3x x x
Using Long Division Before Integrating
• Calculator also can be used
• Now take the integral
192 11
2x dx
x
Change of Variables
• Consider
• Then u = x – 1 and du = dx• But x = _________ and x – 2 = ______________
• So we have
• Finish the integration
3
2
1
x xdx
x
Integrals of Trig Functions
• Note the table of integrals, pg 357• Use these to do integrals involving trig
functions
tan 5 d
1
0
sin cost t dt
Assignment
• Assignment 5.7• Page 358• Exercises 1 – 37 odd
69, 71, 73
Inverse Trigonometric Functions: Integration
Lesson 5.8
Review
• Recall derivatives of inverse trig functions
92
1
2
12
1
2
1sin , 1
11
tan1
1sec , 1
1
d duu u
dx dxud du
udx u dxd du
u udx dxu u
Integrals Using Same Relationships
93
2 2
2 2
2 2
_____________
1_____________
1___________
du uC
aa udu u
Ca u a adu u
Ca au u a
When given integral problems, look for
these patterns
When given integral problems, look for
these patterns
Identifying Patterns
• For each of the integrals below, which inverse trig function is involved?
94
2
4
13 16
dx
x 225 4
dx
x x
29
dx
x
Warning
• Many integrals look like the inverse trig forms• Which of the following are of the inverse trig
forms?
95
21
dx
x
21
x dx
x
21
dx
x
21
x dx
x
If they are not, how are they integrated?
If they are not, how are they integrated?
Try These
• Look for the pattern or how the expression can be manipulated into one of the patterns
96
2
8
1 16
dx
x
21 25
x dx
x
24 4 15
dx
x x
2
5
10 16
xdx
x x
Completing the Square
• Often a good strategy when quadratic functions are involved in the integration
• Remember … we seek _______________• Which might give us an integral resulting in the
arctan function
2 2 10
dx
x x
Completing the Square
• Try these2
22 4 13
dx
x x
2
2
4dx
x x
Rewriting as Sum of Two Quotients
• The integral may not appear to fit basic integration formulas• May be possible to ______________________into
two portions, each more easily handled
2
4 3
1
xdx
x
Basic Integration Rules
• Note table of basic rules• Page 364
• Most of these should be committed to memory
• Note that to apply these, you must create the proper ________ to correspond to the u in the formula
cos sinu du u C
Assignment
• Lesson 5.8• Page 366• Exercises 1 – 39 odd
63, 67
101
Hyperbolic Functions -- Lesson 5.9
• Consider the following definitions
• Match the graphs with the definitions.• Note the identities, pg. 371
sinh2
cosh2
sinhtanh
cosh
x x
x x
e ex
e ex
x
x
Derivatives of Hyperbolic Functions
• Use definitions to determine the derivatives• Note the pattern or interesting results
sinh sinh ??2
cosh cosh ??2
sinhtanh tanh ??
cosh
x x
x x
e e dx x
dx
e e dx x
dxx d
xx dx
Integrals of Hyperbolic Functions
• This gives us antiderivatives (integrals) of these functions
• Note other derivatives, integrals, pg. 371
2
cosh ____________
sinh cosh
sech __________
u du C
u du u C
u du C
Integrals Involving Inverse Hyperbolic Functions
105
1
2 2
1
2 2
-12 2
1
2 2
1sinh
1cosh
1 1tanh
1 1sech
udu C
au au
du Cau au
du Ca u a a
udu C
a au a u
Try It!
• Note the definite integral
• What is the a, the u, the du?• a = 3, u = _________, du = _______________
106
4
21
1
9 4dx
x
4
21
1 2
2 9 4dx
x
Application
• Find the area enclosed by x = -¼, x = ¼, y = 0, and
• Which pattern does this match?• What is the a, the u, the du?
107
2
1
1 4y
x
Assignment
• Lesson 5.9• Page 377• Exercises 1 – 29 EOO
37 – 53 EOO
108