SSC Selection Post 2024 PYQ — Question 58

SSC Selection Post - Higher Secondary Level - 25 June 2024 - Shift 4 • Quantitative Aptitude • Q58

 Evaluate (sin230cos670+cos230sin670cosec2150−tan2750)({{sin23⁰ cos67⁰+cos23⁰sin67⁰} \over cosec^215⁰-tan^275⁰})

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Correct answer: B

Explanation

The correct answer is Option 2 i.e. 1.

Simplify the numerator = (sin23º cos67º + cos23º sin67º)

sin⁡Acos⁡B + cos⁡Asin⁡B = sin⁡(A + B)

So:

⇒ sin⁡(23º + 67º) = sin⁡90º = 1

Simplify the denominator

(cosec215º − tan275º)

tan(75º) = cot(15º) ⇒ tan275º = cot215º

Now use:

cosec⁡2A − cot⁡2A = 1(Identity)

So:

 ⇒ cosec215∘−tan⁡275∘=1\Rightarrow \ cosec^2 15^\circ - \tan^2 75^\circ = 1

⇒ 1/1 = 1