SSC CHSL 2023 PYQ — Question 68

SSC CHSL - 04 Aug 2023 - Shift 1 • Quantitative Aptitude • Q68

What is the value of the expression sinA(1+sinAcosA)+cosA(1+cosAsinA)sinA(1+\frac{sinA}{cosA})+cosA(1+\frac{cosA}{sinA})?

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Correct answer: A

Explanation

The correct answer is Option 1 i.e secA + cosecA.

sinA(1+sinAcosA)+cosA(1+cosAsinA)sinA(1+\frac{sinA}{cosA})+cosA(1+\frac{cosA}{sinA})

⇒ sinA(cosA+sinA)cosA+cosA(sinA+cosA)sinA{sinA(cosA+sinA)\over{cosA}}+{cosA(sinA+cosA)\over{sinA}}

⇒ sin2A(cosA+sinA)+cos2A(sinA+cosA)sinAcosA{{sin^2A(cosA+sinA)+{cos^2A(sinA+cosA)}}}\over sinA cos A

⇒ (cosA+sinA)(sin2A+cos2A)sinAcosA{(cosA +sin A)(sin^2A+cos^2A)}\over sinA cos A

⇒ cosA+sinAsinAcosA{cosA +sin A}\over sinA cos A

⇒ cosAsinAcosA+sinAsinAcosA{{cosA}\over sinA cos A} + {{sinA}\over sinA cosA}

⇒ 1sinA+1cosA{1\over sinA} + {1\over cosA}

⇒ cosecA +  secA