Let , , then number of integral values of so that has exactly one minimum and exactly…

MATHEMATICS · Single correct · A Level · Mathematics · Differentiation · Differentiation

Problem

Let

f(x) = \cos^3 x - \lambda \cos^2 x

0 < x < \pi

, then number of integral values of

\lambda

so that

f(x)

has exactly one minimum and exactly one maximum, is (a) 0 (b) 1 (c) 2 (d) 3