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SSC CGL 2021 PYQ — Question 69

SSC CGL - 23 Aug 2021 - Shift 1 • Quantitative Aptitude • Q69

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If x is a real quantity, what is the minimum value of (25 cos2x + 9 sec2x)?

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Correct answer: A

Explanation

The correct answer is Option 1 i.e 30.

We have to find the minimum value of (25 cos2x + 9 sec2x)

We know that the minimum value of a cos2x + b sec2x = 2ab\sqrt{ab}

a = 25, b = 9

So.

⇒ 2 25×9\sqrt{25\times9}

⇒ 2 × 15 = 30