# Verify Mean Value Theorem for the Function F(X) = 2sin X + Sin 2x on 0,π. - Mathematics

Sum

Verify Mean value theorem for the function f(x) = 2sin x + sin 2x on [0, π].

#### Solution

f(x) = 2sin x + sin 2x on [0, π].
f(x) is continuous in [0, π].
f(x) is differentiable in [0, π].

∴ Mean value theorem is applieable
f(0) = 0, f(x) = 0
f'(x) = 2 cos x + 2 cos 2x
f'(c) = 2 cos c + 2 cos 2c

f'(c) = (f(pi) - f(0))/(pi - 0) = 0

∴ 2 cos c + 2 cos 2c = 0
⇒ (2 cos c - 1)(cos c + 1) = 0

⇒ cos c1/2

⇒ c = pi/3 ∈ (0, π)

Hence mean value theorem is verified.

Concept: Mean Value Theorem
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