Question

prove that
cos9x-cos5x÷sin17x-sin3x=sin2x÷cos10x​

Answer 1

Answer:

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Answer 2

Answer:

LHS = (cos9x - cos5x)/(sin17x-sin3x)

Use the formula,

cosC - cosD = 2sin(C + D)/2.sin(D-C)/2

sinC-sinD = 2cos(C+D)/2.sin(C-D)/2

= {2sin(9x+5x)/2.sin(5x-9x)/2}/{2cos(17x+3x)/2.sin(17x-3x)/2}

=-(sin7x.sin2x)/(cos10x.sin7x)

= - sin2x/cos10x = RHS

Step-by-step explanation:

Proved