Please help me sketch this graph:

f ' (x) > 0 when x<2 and when 2< x <5

f ' (x) < 0 when x > 5

f ' (2) = 0

f " (x) < 0 when x < 2 and 4 < x < 7

f " (x) > 0 when 2 < x < 4 and x > 7

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- Oct 22nd 2007, 11:05 AMbmhNeed help sketching a graph
Please help me sketch this graph:

f ' (x) > 0 when x<2 and when 2< x <5

f ' (x) < 0 when x > 5

f ' (2) = 0

f " (x) < 0 when x < 2 and 4 < x < 7

f " (x) > 0 when 2 < x < 4 and x > 7 - Oct 22nd 2007, 01:14 PMTKHunny
Just one piece at a time.

f ' (x) > 0 when x < 2

Up from the left.

f ' (2) = 0

Level off at x = 2

f ' (x) > 0 when 2 < x < 5

Surprise! Don't trun around and start down at x = 2. (Think about $\displaystyle y\;=\;x^{3}$ at the Origin)

f ' (x) < 0 when x > 5

Okay, NOW turn around and start down. Notice, however, that there must be a point of inflection between x=2 and x=5.

f " (x) < 0 when x < 2 and 4 < x < 7

f " (x) > 0 when 2 < x < 4 and x > 7

Aw! They gave away the point of inflection at x = 4. Further, they gave us another one at x = 7, so don't be wandering off the the bottom of the world.