If x=asinA+bcosA and y=acosA-bsinA, prove that x^2+y^2=a^2+b^2

If x=asinA+bcosA and y=acosA-bsinA,prove that x^2+y^2=a^2+b^2

If x=acosA−bsinA and y=asinA+bcosA, then prove that a2+b2=x2+y2

f x=asinθ+bcosθ and y=acosθ−bsinθ, then prove that x2+y2=a2+b2.