Let f be a function such that f(−6)=−6, f(6)=6, f is differentiable for all real values of x and −1≤f'x≤1 for all real values of x. Prove that f(x)=x for all −6≤x≤6
I tried applying the mean value theorem here but I'm not sure where to start.
I tried applying the mean value theorem here but I'm not sure where to start.