Calculus-Sec-4-2-Solution

4.2 The Shape of a Graph by SGLee - HSKim - JHLee
![]()
1-5. Find the local maximum and minimum values of
. In addition, find the intervals on which
is increasing and decreasing,
and the intervals of concavity and the inflection points, sketch a graph of
.
1.
.
http://matrix.skku.ac.kr/cal-lab/cal-4-2-1.html
![]()
![]()
![]()
![]()
(a) local maximum:
local minimum: ![]()
(b) increasing on ![]()
decreasing on ![]()
(c) inflection point at ![]()
concave down on ![]()
concave up on ![]()
2. ![]()
http://matrix.skku.ac.kr/cal-lab/cal-4-2-2.html
(a) local minimum: ![]()
(b) increasing on ![]()
decreasing on ![]()
(c) inflection point at ![]()
concave down on ![]()
concave up on ![]()
3.
.
![]()
![]()
![]()
![]()
(a) local maximum: ![]()
local minimum: ![]()
(b) increasing on ![]()
decreasing on ![]()
(c) inflection point at ![]()
concave down on ![]()
concave up on ![]()
To find local maximum and minimum, use the next sage code.
To find inflection points, we calculate the second derivative.
4. ![]()
![]()
(a) local maximum : No
local minimum : ![]()
(b) increasing on ![]()
decreasing on ![]()
(c) inflection point : No
concave up on ![]()
5. ![]()
http://matrix.skku.ac.kr/cal-lab/cal-4-2-5.html
(a) Maximum : 1, Minimum : 0
(b) interval of increase : ![]()
interval of decrease : ![]()
(c) inflection point at 변곡점은 0.722, -0.722
concave down on
6-11. Find the inflection points of
In addition, find intervals in which the graph of
is concave upward or concave downward.
6. ![]()
(a) inflection point at ![]()
(b) concave down on ![]()
concave up on ![]()

7. ![]()
![]()
![]()
![]()
![]()
![]()
(a) inflection point at ![]()
(b) concave up on ![]()
concave down on ![]()

8.
, ![]()
![]()
(a) inflection point at ![]()
(b) concave down on ![]()
concave up on ![]()
9. ![]()
http://matrix.skku.ac.kr/cal-lab/cal-4-2-9.html
(a) critical point at
, inflection point at ![]()
(b) concave down on ![]()
concave up on
.
10. ![]()
![]()
![]()
![]()
![]()
![]()
(a) inflection point at ![]()
(b) concave up on ![]()
concave down on ![]()
11. ![]()
(a) inflection points :
and ![]()
(b) concave down on ![]()
concave up on ![]()
12-15. Find the vertical and horizontal asymptotes of
.
12. ![]()
![]()
vertical asymptote ![]()
![]()
horizontal asymptote ![]()
14. ![]()
![]()
![]()
horizontal asymptote ![]()
16-18. Sketch the graph of
using the following information.
(a) Find the local maximum and minimum values of
.
(b) Find the intervals of increase or decrease.
(c) Find the inflection points of
and intervals of concavity.
(d) Find the vertical and horizontal asymptotes.
16. ![]()
![]()
(a) local maximum : No
local minimum : No
(b) decreasing on ![]()
(c) inflection point at ![]()
concave up on ![]()
concave down on ![]()
(d) vertical asymptote : ![]()
horizontal asymptote : ![]()
17. ![]()
![]()
, ![]()
(a) local minimum at ![]()
(b) increasing on ![]()
decreasing on ![]()
(c) inflection point : No
concave up on ![]()
(d) vertical asymptote: ![]()
horizontal asymptote: No

18.
, ![]()
![]()
and ![]()
and
;
and ![]()
(a) local minimum at ![]()
local maximum : ![]()
(b) increasing on ![]()
decreasing on ![]()
(c) inflection point at ![]()
concave up on ![]()
concave down on ![]()
(d) vertical asymptote: No
horizontal asymptote: ![]()
19. Find all the values of a such
has
different roots.
![]()
Let
. Then will have one local maximum and one local minimum. There will be
roots if and only if the maximum is positive and the minimum is negative.
and
.
![]()
![]()
Note that
and
. Hence
has local maximum at
and local minimum at
. Therefore, if
there will be
roots.
20. Find the minimum constant
for which
for all real
.
http://math1.skku.ac.kr/home/pub/1040/
![]()
![]()
![]()
, ![]()
![]()
local minimum at ![]()
![]()
Therefore,
.
21. Find
so that
has two inflection points at
and
.
![]()
![]()
![]()
and so
, ![]()
and so
.
22. Let
.
(a) Find
and
.
(b) Find the vertical and horizontal asymptotes of
.
(c) Sketch the graph of
using (a) and (b).
(a) ![]()
![]()
(b)
, ![]()
vertical asymptote ![]()
horizontal asymptote ![]()
(c)
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23. Let
and
be increasing functions. Prove that
is increasing function.
![]()
For
,
, ![]()
![]()
Therefore,
is increasing.
24. Prove the Concavity Test.
![]()
(a) By Increasing Test
If
on an interval
then
is increasing on
.
So
is concave upward on
.
Part (b) is proved similarly.
26. Let
. Find the local maximum, minimum values and inflection points of
. Sketch the graph of
.
http://matrix.skku.ac.kr/cal-lab/cal-4-2-26.html
local maximum : ![]()
local minimum : No
inflection point :
27. Let
. Find the local maximum, minimum values and inflection points of
.
http://matrix.skku.ac.kr/cal-lab/cal-4-2-27.html
local maximum : ![]()
local minimum : No
inflection point : ![]()