A Sufficient-Necessary Trig Condition

Problem

Determine whether the statement "ksinxcosx<xk\sin x\cos x<x for all x(0,π2)x\in\left(0,\dfrac{\pi}2\right)" is a sufficient condition, a necessary condition, both, or neither, for "k<1k<1". Justify your answer.

Answer

Solution

Difficulty6/10
Topicstrigonometry, Logic, Monotonicity, inequality

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