Question

If x=r cosA and y=r sinA then prove that x square+y square=r sauare​

Answer 1

Solution:

It is given that,.

x = rcosA

=> x² = (rcosA)²

=> x² = r²cos²A ----(1)

y = rsinA

=> y² = (rsinA)²

=> y² = r²sin²A ----(2)

Add (1) &(2) ,we get

=>x²+y² = r²cos²A+r²sin²A

= r²(cos²A+sin²A)

= r²

$\boxed {cos^{2}A+sin^{2}A=1}$

••••