Posted by Anonymous on .
Use the 2nd derivative test to find the extremer of f on the interval [0,2PI]
f(x)=2cosx+sin 2x

calculus 
Anonymous,
Ack, I forgot, I don't seem to have a problem with numbers but when it comes to the sin and cos...I am not sure how to derive them. I want to say that 2cosx would end up being something like 2sinx (x)...but then I feel like there's something wrong w/that scenario.

calculus 
Reiny,
first derivative:
2sinx + 2cos 2x
2nd derivative:
2cosx  4sin 2x
take it from there