On which of the following intervals, the function x200+sinx − 1  is strictly increasing?

f'(x)=200x199+cos x For x∈(0,1 )  and (0,π2) cos x  and x  are both positive ⇒  f(x)  is increasing For x∈(π2,π), x>1  hence 200x199 > cos x  ⇒  f(x)  is increasing