Condition (1):

Since, f(x)=sinx+cosx is a trigonometric function and we know every trigonometric function is continuous.

⇒ f(x)= sinx+cosx is continuous on .

Condition (2):

Here, f’(x)= cosx-sinx which exist in .

So, f(x)= sinx+cosx is differentiable on

Condition (3):

Here, f(0)=sin0+cos0=1

And

i.e.

Conditions of Rolle’s theorem are satisfied.

Hence, there exist at least one such that f’(c)=0

i.e. cosc-sinc =0

i.e.

Value of

Thus, Rolle’s theorem is satisfied.