Question

prove that sin 3x is equal to 3 sin x - 4 sin square x​

Answer 1

Answer:

This the answer

Step-by-step explanation:

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Answer 2

Answer:

Step-by-step explanation:

sin(3x)=sin(2x+x)

=  sin2x.cosx + cos2x.sinx

= (2sinx.cosx).cosx + (1-2sin²x).sinx

=2sinx.cos² + sinx - 2sin³x

= 2sinx(1-sin²x) + sinx -2sin³x

= 2sinx - 2sin³x + sinx - 2sin³x

= 3sinx - 4sin³x

Q.E.D.