section 2.8 - continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt....

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Section 2.8 - Continuity

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Page 1: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

Section 2.8 - Continuity

Page 2: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

2f x x 2x 1

continuous

2

1f x

x 1

continuous

2

xf x

x x

x

x x 1

pt. discontinuity at x = 0

inf. discontinuity at x = 1

2

x 3f x

x 9

x 3

x 3 x 3

pt. discontinuity at x = 3

inf. discontinuity at x = -3

2

2x 3 x 1f x

x x 1

2 1 3 1

21 1

continuous

1

x 1 x 2f x 2

3 x x 2

12 1 2

2

3 2 1

jump discontinuity at x = 2

Page 3: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

Find the value of a which makes the function below continuous

3

2

x x 2f x

ax x 2

3

2

3

2

x x 2f x

ax x

2 8

2 4a2 a

4a 8 a 2

No Calculator

Page 4: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

Find (a, b) which makes the function below continuous

2 x 1

f x ax b 1 x 3

2 x 3

As we approach x = -1 2 = -a + b

As we approach x = 3 -2 = 3a + b

4 4aa 1 b 1

1,1

No Calculator

Page 5: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

tanxConsider the function f defined on x by f x

2 2 sinx

No Calculator

for all x . If f is continuous at x = , then f

A. 2 B. 1 C. 0 D. -1 E. -2

sinx

tanx cos xf xsinx sinx

sinx 1

cos x sinx 1 1

1 Dcos x cos

Page 6: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

No Calculator

Which function is NOT continuous everywhere?

2 / 3

2

2

2

A. y x

B. y x

C. y x 1

xD. y

x 14x

E. yx 1

undefined at x = -1

Page 7: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

Calculator Required

Which of the following is true about 2

2

x 1f x ?

2x 5x 3

I. f is continuous at x = 1 II. The graph of f has a vertical asymptote at x = 1III. The graph of f has a horizontal asymptote at y = 1/2

A. I B. II C. III D. II, III E. I, II, III

I. f(1) results in zero in denominator….NO

II. Since x – 1 results in 0/0, it is a HOLE, NOT asymptote

III. 2

2x

x 1lim

2x 5x 3

2

2x

x 2x 1lim

2x 5x 3

X X

X X

1

2

Page 8: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

The graph of the derivative of a function f is shown below.Which of the following is true about the function f? I. f is increasing on the interval (-2, 1) II. f is continuous at x = 0III. f has an inflection point at x = -2

A. I B. II C. III D. II, III E. I, II, III

NOYESYES

Calculator Required

Page 9: Section 2.8 - Continuity. continuous pt. discontinuity at x = 0 inf. discontinuity at x = 1 pt. discontinuity at x = 3 inf. discontinuity at x = -3 continuous

Calculator RequiredLet m and b be real numbers and let the function f be defined by:

21 3bx 2x x 1

f xmx b x 1

If f is both continuous and differentiable at x = 1, then:A. m 1, b 1

B. m 1, b 1

C. m 1, b 1

D. m 1, b 1

E. none of these

3b 4x x 1f ' x

m x 1

3b 4 m 1 3b 2 m b

3b m 4

2b m 3

If x = 1