Question
How do i find the points of inflection for: f(x)= (1/12)x^4 -2x^2 +15
The answers are (2, 25/3) and (-2, 25/3) but i don't know how to get the answers. Can someone show me step by step?
The answers are (2, 25/3) and (-2, 25/3) but i don't know how to get the answers. Can someone show me step by step?
Answers
Reiny
You will need the second derivative, which is easily found to be x^2 - 4
setting this equal to zero gives us
x^2 = 4
x = ±2
plug x = 2 back into the original to get f(2) = (1/12)(16) - 2(4) + 15
= 25/3
do the same for x = -2
and you are done.
setting this equal to zero gives us
x^2 = 4
x = ±2
plug x = 2 back into the original to get f(2) = (1/12)(16) - 2(4) + 15
= 25/3
do the same for x = -2
and you are done.