Hey i was having a problem with a hw problem
the function f(x)=(cosx)^2 +2cosx over one complete period beginning with x=0
First we have to find all values of x in this period when f(x)=0.
I know the period is 0-2π by looking at the graph however I don't know how to figure it out analyitically though. So i found the zeroes but again i dont know how to do it analytically because i am not got with sin and cos
Second we have to find all values of x in the period at which the function has a minimum.
3rd we have to find when the period is concave up but i don't know how to find the 2nd derivative of a cos