# maths-

posted by
**anoynomous**
.

A and B are two different values of C lying between 0 and 360 which satisfy the equation (p cosC + q sinC=r) then prove that cos(A+B)=(p^2- q^2)/(p^2+ q^2)

posted by
**anoynomous**
.

A and B are two different values of C lying between 0 and 360 which satisfy the equation (p cosC + q sinC=r) then prove that cos(A+B)=(p^2- q^2)/(p^2+ q^2)