As we know that the sine functions are continuous and differentiable on R.
Let us find the values of the function f at an extreme
Here, f(0) = f(π/6), therefore there exist a c ∈ (0,π/6) such that f'(c) = 0.
Let us find the derivative of f(x)
Since, f'(c) = 0
Thus, Rolle'* theorem is verified.