SSC CHSL 15 Oct 2020 Shift 3 Paper

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Question : 51 of 100

Marks: +1, -0

Quantitative Aptitude

Find the value of

{\cos ^{2} 30-\sin ^{2} 30}/{\sin ^{2} 15°+\cos ^{2} 15°}

${1}/{2}$
1
$1-\√{3}$
0

Solution:

Given,

{\cos ^{2} 30-\sin ^{2} 30}/{\sin ^{2} 15°+\cos ^{2} 15°}

We know that,

\cos 30°={\√{3}}/{2}

,

\sin 30°={1}/{2}

and

\sin ^{2} \θ+\cos ^{2} \θ=1

∴

{({\√{3}}/{2})^{2}-({1}/{2})^{2}}/{1}

={3}/{4}-{1}/{4}={3-1}/{4}

={2}/{4}={1}/{2}

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