Q. 12 A4.0( 5 Votes )

If sin 3A = cos(A – 26o), where 3A is an acute angle, find the value of A.

Answer :

sin 3A = cos (A-26°) …(i)

We know that


Sin θ = cos (90° - θ)


So, Eq. (i) become


Cos (90° - 3A) = cos (A -26°)


On Equating both the sides, we get


90° - 3A = A – 26°


-3A - A = -26° -90°


-4A = -116°


A = 29°


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