Qus: (sin A−2 sin3A)/ (2 cos3A−cos A)=

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A. tan A
B. cot A
C. sec A
D. 1

Solution

A. tan A

Explanation

(sin A−2 sin3A)/ (2 cos3A−cos A) = (sin A (1−2 sin2A))/ (cos A(2 cos2A−1))

= (sin A (sin2A+cos2A−2 sin2A)) / (cos A (2 cos2A− (sin2A+cos2A))

= (sin A (cos2A−sin2A)) / (cos A (cos2A−sin2A))

=tan A