Q. 204.3( 27 Votes )
Prove that

Answer :
=Sin3x+sin2x-sinx
= (sin3x- sinx)+sin2x
= ( 2cossin
) + sin2x
= 2cos2xsinx +sin2x
= 2cos2xsinx + 2sinxcosx
= 2sinx (cos2x + cosx )
= 2sinx (2cos cos
)
= 4sinxcos cos
Using the formula,
sinA - sinB = 2cos sin
cosA + cosB = 2coscos
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