Question

If xcose - ysino = a, xsine + ycos 0 = b, prove that
X2+y2=a2+b2.​

Answer 1

Answer:

a^2+b^2

=(xcose-ysino) ^2+(xsine+ycos0)^2

=x^2(cose)^2+y^2(sino)^2-2*xcose*ysino+x^2(sine)^2+y^2(coso)^2+2*xsine*ycos 0

= x^2(cose)^2+x^2(sine)^2+y^2(sino)^2+y^2(coso)^2

=x^2((cose) ^2+sine^2)+y^2((sino) ^2+(cos0)^2)

=x^2+y^2

proved......