Question

Find the intervals where the function, f(x)= x-cosx ; (0, 2pie), is increasing and decreasing.

Answer 1

take derivative of f(x)
f'(x) = 1+sin(x)
function is increasing when f'(x)>0 -> sin(x)>-1
function is decreasing when f'(x)<0 -> sin(x)<-1
Note that the sin function is always greater than or equal to -1
so f(x) is always increasing

Answer 2

thanks a lot!

Answer 3

your welcome