Question

Prove that
cos 7x + Cos 5x / Sin 7x - Sin 5x = Cot x​

Answer 1

Step-by-step explanation:

by separate

cos7x+cos5x

then,

cosx+cosy=2cos x+y/2 cos x-y/2

now,

putting x=7x & y =5x

=2cos 7x+5x/2 cos 7x-5x/2

=2cos 12x/2 cos 2x/2

=2cos6x cosx

again,

sin7x-sin5x,

sinx-siny=2cos x+y/2 sin x-y/2

putting x=7x& y=5x

=2cos 7x+5x/2 sin 7x-5x/2

=2cos6x sinx

Now,

=cos7x+cos5x/sin7x-sin5x

=2cos6x cosx/2cos6x sinx

=cosx/sinx

=cotx

=R.H.S

Hence

L.H.S=R.H.S PROVED.....

Answer 2

Answer:

heres ur answer...

Step-by-step explanation: