Verify Rolle’s theorem for each of the following functions:
Condition (1):
Since, f(x)=e-x sinx is a combination of exponential and trigonometric function which is continuous.
⇒ f(x)= e-x sinx is continuous on [0,π].
Condition (2):
Here, f’(x)= e-x (cosx – sinx) which exist in [0,π].
So, f(x)= e-x sinx is differentiable on (0,π)
Condition (3):
Here, f(0)= e-0 sin0=0
And f(π)= e-πsinπ =0
i.e. f(0)=f(π)
Conditions of Rolle’s theorem are satisfied.
Hence, there exist at least one cϵ(0,π) such that f’(c)=0
i.e. e-c (cos c – sin c) =0
i.e. cos c-sin c = 0
i.e.
Value of
Thus, Rolle’s theorem is satisfied.