Math: Calculus
posted by NEED HELP!!!! .
Answer the following questions for the function
f(x)=sin(x/4)^2
defined on the interval [12.266371, 2.241593].
Rememer that you can enter pi for as part of your answer.
a.)f(x) is concave down on the interval ____.
b.) A global minimum for this function occurs at ____.
c.) A local maximum for this function which is not a global
maximum occurs at _____.
d.) The function is increasing on the region _____.

I REALLY NEED HELP ANSWERING THIS. I mange to get b and c but i'm stuck on the other two

What did you get for b & c?
For concavity and increasing, you need to calculate f"(x) within the interval.
Concavity changes when f"(x)=0. f"(x)>0 is concave upwards, and vice versa.
Function's and increasing/decreasing changes only when f'(x)=0. When f'(x)>0 it is increasing, and vice versa.