I am trying to find absolute maximum and absolute minimum values for$\ f(x)=\cos(x)+\sin(2x)$ on the interval $\ [0,\fracπ2]$.
I started off by finding the derivative:
$\ f'(x)=-\sin x+2\cos(2x)$
Then I tried to find the critical numbers. But that's where I ran amuck. I came up with:
How do I go about solving for x?