Q23 of 25 Page 3

Find the general solution of the equation sin x + sin 3x + sin 5x = 0.

Given equation is


sin x + sin 3x + sin 5x = 0

Formula to be used:


Applying the formula we get,

(sin x+ sin 5x) + sin 3x = 0

+ sin 3x = 0


2 sin 3x cos (-2x) + sin 3x= 0

( ∵ cos (-θ ) = cos θ )

sin 3 x (2 cos 2 x + 1) = 0 


sin 3x = 0 or 2 cos 2x +1 = 0


Now,



Now, 2 cos 2x +1 = 0




where n Z and Z is set of integers


where n Z


the general solution of the equation is


where n Z and Z is set of integers

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