Section 2.6 Examples

SECTION 2.6
2.6
S Click here for solutions.
1–8 Evaluate the limit and justify each step by indicating the
appropriate properties of limits.
1. lim
1
x sx
3. lim
x⫹4
x 2 ⫺ 2x ⫹ 5
xl⬁
共1 ⫺ x兲共2 ⫹ x兲
5. lim
x l ⫺⬁ 共1 ⫹ 2x兲共2 ⫺ 3x兲
7. lim
xl⬁
1
3 ⫹ sx
2.
lim
xl⬁
5 ⫹ 2x
3⫺x
7t ⫹ 4t
2t 3 ⫺ t 2 ⫹ 3
3
4. lim
tl⬁
6.
8.
lim
xl⬁
lim
xl⬁
冑
2x 2 ⫺ 1
x ⫹ 8x 2
sin 2x
x2
rl⬁
r4 ⫺ r2 ⫹ 1
r5 ⫹ r3 ⫺ r
s1 ⫹ 4x 2
11. lim
xl⬁
4⫹x
13. lim
Stewart: Calculus: Early Transcendentals, Seventh Edtion. ISBN: 0538497904. © 2012 Cengage Learning. All rights reserved.
xl⬁
1 ⫺ sx
1 ⫹ sx
15. lim (sx 2 ⫹ 1 ⫺ sx 2 ⫺ 1 )
xl⬁
16. lim (s1 ⫹ x ⫺ sx )
xl⬁
3
3
17. lim (s
1⫹x⫺s
x)
18. lim (sx 2 ⫹ x ⫹ 1 ⫹ x)
19. lim ( x ⫹ sx )
20. lim 共x 3 ⫺ 5x 2 兲
xl⬁
t l⫺⬁
6t 2 ⫹ 5t
共1 ⫺ t兲共2t ⫺ 3兲
sx 2 ⫹ 4x
12. lim
x l⫺⬁
4x ⫹ 1
14. lim (sx 2 ⫹ 3x ⫹ 1 ⫺ x)
xl⬁
x l⫺⬁
x ⫺1
x6 ⫹ 1
7
21. lim
xl⬁
22. lim e ⫺x
2
xl⬁
23. lim 共x 2 ⫺ x 4 兲
xl⬁
xl⬁
10. lim
x l ⫺⬁
xl⬁
25. lim
9–26 Find the limit.
9. lim
■
L I M I T S AT I N F I N I T Y; H O R I Z O N TA L A S Y M P TOT E S
A Click here for answers.
xl⬁
LIMITS AT INFINITY; HORIZONTAL ASYMPTOTES
24. lim
x3 ⫺ 1
x4 ⫹ 1
26. lim
x
sx ⫺ 1
xl⬁
sx ⫹ 3
x⫹3
xl⬁
27. Guess the value of the limit
lim x 2 sin
xl⬁
5
x2
by evaluating f 共x兲 苷 x 2 sin共5兾x 2 兲 for x 苷 1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 20, 50, and 100. Then confirm your guess by evaluating
this limit exactly.
1
■
SECTION 2.6
2.6
LIMITS AT INFINITY; HORIZONTAL ASYMPTOTES
ANSWERS
E Click here for exercises.
1. 0
8. 0
14.
3
2
20. ⫺⬁
26. ⬁
2. ⫺2
9. 0
3. 0
10. ⫺3
15. 0
21. ⬁
16. 0
22. 0
4.
S Click here for solutions.
7
2
5.
1
6
6.
11. 2
12. ⫺
17. 0
18. ⫺
23. ⫺⬁
1
2
1
4
1
2
24. 0
7. 0
13. ⫺1
19. ⬁
25. 0
27. 5
Stewart: Calculus: Early Transcendentals, Seventh Edtion. ISBN: 0538497904. © 2012 Cengage Learning. All rights reserved.
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