Answers to Exercises









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213399 Answers to Exercises

Answers to Exercises

I am much indebted to Anthony Petrello for some of the answers to the exer cises.

I, §2, p. 13

1. -3 < x < 3 2. - 1 x

0 3. -j3 x -1 or 1 x j3

4. x < 3 or x > 7 5. - 1 < x < 2 6. x < -lor

x > 1 7. - 5 < x < 5

8. - 1 x 0 9. x 1 or x = 0 10. x -10 or x = 5

11. x -10 or x = 5 12. x 1 or x = -! 13. x < -4

14. -5

17. -2 < x < 8 18. 2 < x < 4 19. -4 < x < 10 20. x < -4 and x> 10

21. x < -10 and x > 4

I, §3, p. 17

1.

2. (2x 1) 3. 0, 2, 108 4. 2z -Z2, 2w - w

2

5. x # j2 or -j2. f(5) = b 6. All x. f(27) = 3

7. (a)

1 (b) 1 (c) -1 (d) -1 8. (a) 1 (b) 4 (c) 0 (d) 0

9. (a) -2 (b) -6 (c) x2+4x-2 10. 2

II. (a) odd (b) even (c) odd (d) odd

I, §4, p. 20

1. 8 and 9 2.! and -1 3. /6 and 2 4. and 2

1/3

5. -h and! 6. 9 and 8

7. -! and -1 8.! and! 9. 1 and -! 10. -5:2 and!

A2 ANSWERS TO EXERCISES

II. Yes. Suppose a is negative, so write a = -b where b is positive. Let c be a positive number such that c" = b. Then (-c)" = a because (-1)" = -1 since n is odd.

II, §1, p. 24

3. x negative, y positive 4. x negative, y negative

II, §3, p. 33

5. y = + i 6. y = -ix + S 7. x = J2

9 9j3

8. y = --;:;-x + 4 ---;:;-9. y = 4x -3 10. y = -2x + 2

",3+3 ",3+3

II. y= -!x+3+ J'!-12. y=j3x+S+j3 19. -! 20.-8

21. 2 + j2 22.!<3 + j3) 23. y = (x -n>(J22_ n) + 1

24. 25. y= -(x+ l)(j23+ 1)+2

26. y = (x + 1)(3 + j2) + j2 29. (a) x = -4, y = -7 (b) x = y = i

(c) x = -!, y = 1 (d) x = -6, Y = -5

II, §4, p. 35

1.J97 2.j2 3.Js2 4.Ji3 5.!j5 6.(4,-3) 7. SandS 8.(-2,5)

9. Sand 7

II, §8, p. 51

5. (x -2)2 + (y + 1)2 = 25 6. x

2 + (y -

1)2 = 9 7. (x + \)2 + y2 = 3

8. y + ¥ = 2(x + W 9. y - 1 = (x + 2)2 10. y + 4 = (x -\)2

II. (x + 1)2 + (y -2)2 = 2 12. (x -2)2 + (y -\)2 = 2

13. x + ¥-= 2(y + !)2 14. x-I = (y + 2)2

III, §1, p. 61

1. 4 2. -2 3. 2 4. i S. -! 6. 0 7. 4 8. 6 9. 3 10. 12 II. 2

12. 3 13. a

ANSWERS TO EXERCISES

III, §2, p. 70

Tangent line at x = 2 Slope at x = 2

1. 2x y = 4x - 3 4

2. 3x2 y = 12x -16 12

3. 6x2 y = 24x -32 24

4.6x y = 12x -12 12

5.2x y = 4x - 9 4

6. 4x + I Y = 9x - 8 9

7. 4x -3 Y = 5x - 8 5

3x2

8. 2+2 y = 8x - 8 8

9. Y = + 1 -(x + 1)2 -9 2

Y = +.!j

2 10. - (x + 1)2 -9

III, §3, p. 75

2 I 1

I. 4x + 3 2. -2 3. 2 4. 2x + 1 5. -2 6. 9x

2 (2x + 1) (x + 1) (2x -1) 3x 2

10. 2 + I 11. _2/X2 12. -3/x

2

13. -2/(2x -W 14. -3/(3x + 1)2 15. -1/(x + 5)2 16. -I/(x _ 2)2

17. -2x-3 18. -2(x + 1)-3

III, §4, p. 78

1. X4 + 4x

3h + 6x 2 h 2 + 4xh3 + h4 2. 4x3

3. (a) jx-

I/3 (b) (c) 4. Y = 9x -8 5. Y = tx + t slope t -3 7 -3 1 -fi 1

6. Y = Y x + 32' slope y 7. Y = 2-fi x + 2' slope 2-fi

8. (a) !5-

3/4 (b) _!r

Answers to Exercises

I am much indebted to Anthony Petrello for some of the answers to the exer cises.

I, §2, p. 13

1. -3 < x < 3 2. - 1 x

0 3. -j3 x -1 or 1 x j3

4. x < 3 or x > 7 5. - 1 < x < 2 6. x < -lor

x > 1 7. - 5 < x < 5

8. - 1 x 0 9. x 1 or x = 0 10. x -10 or x = 5

11. x -10 or x = 5 12. x 1 or x = -! 13. x < -4

14. -5

17. -2 < x < 8 18. 2 < x < 4 19. -4 < x < 10 20. x < -4 and x> 10

21. x < -10 and x > 4

I, §3, p. 17

1.

2. (2x 1) 3. 0, 2, 108 4. 2z -Z2, 2w - w

2

5. x # j2 or -j2. f(5) = b 6. All x. f(27) = 3

7. (a)

1 (b) 1 (c) -1 (d) -1 8. (a) 1 (b) 4 (c) 0 (d) 0

9. (a) -2 (b) -6 (c) x2+4x-2 10. 2

II. (a) odd (b) even (c) odd (d) odd

I, §4, p. 20

1. 8 and 9 2.! and -1 3. /6 and 2 4. and 2

1/3

5. -h and! 6. 9 and 8

7. -! and -1 8.! and! 9. 1 and -! 10. -5:2 and!

A2 ANSWERS TO EXERCISES

II. Yes. Suppose a is negative, so write a = -b where b is positive. Let c be a positive number such that c" = b. Then (-c)" = a because (-1)" = -1 since n is odd.

II, §1, p. 24

3. x negative, y positive 4. x negative, y negative

II, §3, p. 33

5. y = + i 6. y = -ix + S 7. x = J2

9 9j3

8. y = --;:;-x + 4 ---;:;-9. y = 4x -3 10. y = -2x + 2

",3+3 ",3+3

II. y= -!x+3+ J'!-12. y=j3x+S+j3 19. -! 20.-8

21. 2 + j2 22.!<3 + j3) 23. y = (x -n>(J22_ n) + 1

24. 25. y= -(x+ l)(j23+ 1)+2

26. y = (x + 1)(3 + j2) + j2 29. (a) x = -4, y = -7 (b) x = y = i

(c) x = -!, y = 1 (d) x = -6, Y = -5

II, §4, p. 35

1.J97 2.j2 3.Js2 4.Ji3 5.!j5 6.(4,-3) 7. SandS 8.(-2,5)

9. Sand 7

II, §8, p. 51

5. (x -2)2 + (y + 1)2 = 25 6. x

2 + (y -

1)2 = 9 7. (x + \)2 + y2 = 3

8. y + ¥ = 2(x + W 9. y - 1 = (x + 2)2 10. y + 4 = (x -\)2

II. (x + 1)2 + (y -2)2 = 2 12. (x -2)2 + (y -\)2 = 2

13. x + ¥-= 2(y + !)2 14. x-I = (y + 2)2

III, §1, p. 61

1. 4 2. -2 3. 2 4. i S. -! 6. 0 7. 4 8. 6 9. 3 10. 12 II. 2

12. 3 13. a

ANSWERS TO EXERCISES

III, §2, p. 70

Tangent line at x = 2 Slope at x = 2

1. 2x y = 4x - 3 4

2. 3x2 y = 12x -16 12

3. 6x2 y = 24x -32 24

4.6x y = 12x -12 12

5.2x y = 4x - 9 4

6. 4x + I Y = 9x - 8 9

7. 4x -3 Y = 5x - 8 5

3x2

8. 2+2 y = 8x - 8 8

9. Y = + 1 -(x + 1)2 -9 2

Y = +.!j

2 10. - (x + 1)2 -9

III, §3, p. 75

2 I 1

I. 4x + 3 2. -2 3. 2 4. 2x + 1 5. -2 6. 9x

2 (2x + 1) (x + 1) (2x -1) 3x 2

10. 2 + I 11. _2/X2 12. -3/x

2

13. -2/(2x -W 14. -3/(3x + 1)2 15. -1/(x + 5)2 16. -I/(x _ 2)2

17. -2x-3 18. -2(x + 1)-3

III, §4, p. 78

1. X4 + 4x

3h + 6x 2 h 2 + 4xh3 + h4 2. 4x3

3. (a) jx-

I/3 (b) (c) 4. Y = 9x -8 5. Y = tx + t slope t -3 7 -3 1 -fi 1

6. Y = Y x + 32' slope y 7. Y = 2-fi x + 2' slope 2-fi

8. (a) !5-

3/4 (b) _!r
  1. log x derivative formula
  2. log x derivative by first principle
  3. log x derivative proof
  4. log x dérivée
  5. log x differentiation
  6. log x^2 derivative
  7. 1/log x derivative
  8. log x^3 derivative