JEE MATHEMATICS MCQ: TRIGONOMETRIC EQUATIONS

1 Easy

1 of 1

Application +4 | -1

\cos ^{-1}(x / 2)+\cos ^{-1}(y / 3)=\theta

, then

9 x^2-12 x y \cos \theta

+4 y^2

is equal to

View answer and explanation

Correct option: C

36 \sin ^2 \theta

Option C,

36 \sin^2 \theta

, is correct because by using the cosine addition formula and simplifying, we can derive that

9x^2 - 12xy \cos \theta + 4y^2 = 36 \sin^2 \theta

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