Question

prove
that
cos 9x-cos 5x÷sin 17x-sin 3x =sin 2x÷cos 10x​

Answer 1

Answer:

Hey!!

Step-by-step explanation:

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

$<marquee > Hope it's help you$