Question

Sin (x-y) cosx-Cos(x-y) Sinx = -siny​

Answer 1

Answer:

to prove sin(x-y)cos x - cos(x-y)sin x = - siny

=> sin(x-y) cos x= sin x cos x cos y - cos² x sin y (1)

Step-by-step explanation:

=>cos (x-y) sin x = cos x sin x cos y + sin² x sin y (2)

1 - 2

=> - cos² x sin y - sin² x sin y

=> - sin y [ cos² x + sin² x ]

=> - sin y [ cos² x + sin² x = 1 ]