need 2 find the turning point of the graph f(x)=cosx-xsinx so i differentiatied this and got f'(x)=-2sinx-xcosx
so i made this equal to 0 and worked my way down as follows:

0=-2sinx-xcosx
2sinx=-xcosx
2tanx=-x
2tanx+x=0

i dont kno where to go from here, any ideas.