Question

. If a cos θ + b sin θ =m and a sin θ -b cosθ = n, then show that a2 + b2-m2 + n2.

Plz tell The correct answer.​

Answer 1

Answer:

Sol: We have, a cos θ + b sin θ = m (i)

and a sin θ -bcos θ = n (ii)

On squaring Eqs. (i) and (ii) and then adding the resulting equations, we get

m² + n² = (a cos 0 + b sin 0)² + (a sin 0-b cos 0)² =a² cos² 0 + b² sin² 0 + 2ab sin cos 0 + a² sin² 0 + b² cos² 0 - 2ab sin 0 cos 0

=a²(cos² 0 + sin² €) + b²(sin² 0 + cos² 0) = a² + b²

I HOPE THIS ANSWER IS HELPFULL