SSC CGL 2024 PYQ — Question 69

SSC CGL - 18 Sep 2024 - Shift 1 • Quantitative Aptitude • Q69

If sec(t) = xyx\over y, then cot(t) is equal to:

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Correct answer: A

Explanation

The correct answer is Option 1 i.e. yx2−y2y\over{\sqrt{x^2 - y^2}}.

sec(t) = xyx\over y 

⇒ sec(t) = 1/cos(t)

⇒ cos(t) = yxy\over x

We know that,

⇒ sin2(t) + cos2(t) = 1

⇒ sin2(t) + (yxy\over x )2 = 1

⇒ sin2(t) = 1 - (yxy\over x )2

⇒ sin2(t) = (x2−y2x2{x^2-y^2}\over x ^2)

⇒ sin(t) = x2−y2x2\sqrt{{x^2-y^2}\over x ^2}

Now,

⇒ cot(t) = cos(t)/sin(t)

⇒ cot(t) = yxy\over x /x2−y2x2\sqrt{{x^2-y^2}\over x ^2}

⇒ cot(t) = yx2−y2{y\over {x^2-y^2}}