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MathsMediumMCQ2021 · 27 Aug Shift 1

Q72.If (sin−1 x)2 −(cos−1 x)2 = a; 0 < x < 1, a ≠0, then the value of 2x2 −1 is (1) cos( 2aπ ) (2) sin( 2aπ ) (3) cos( 4aπ ) (4) sin( 4aπ )

What This Question Tests

The question requires applying the fundamental identity between sin⁻¹x and cos⁻¹x to simplify the given expression and then relate it to a trigonometric function of 'a'.

Concepts Tested

Properties of inverse trigonometric functionsBasic trigonometric identitiesSolving equations with inverse trigonometric functions

Formulas Used

sin⁻¹x + cos⁻¹x = π/2

cos(2θ) = 2cos²θ - 1

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