SSC CHSL 17 Mar 2020 Shift 3 Paper

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Question : 74 of 100

Marks: +1, -0

If

\sin \θ={4}/{5}

, find the value of

\sin 3 \θ

.

${32}/{45}$
${44}/{125}$
${64}/{125}$
${12}/{25}$

Solution:

Given,

\sin \θ={4}/{5}

We know that,

\sin 3 \θ=3 \sin \θ-4 \sin ^{3} \θ

⇒

\sin 3 \θ=3 ×{4}/{5}-4 ×({4}/{5})^{3}

⇒

\sin 3 \θ={12}/{5}-{256}/{125}

⇒

\sin 3 \θ={300-256}/{125}

∴

\sin 3 \θ={44}/{125}

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