Question

If x=a sin theta and y= a cos theta find the value of x2 +y2.

Answer 1

hy
Given

x=a sin theta
y= a cos theta

x sq + y sq

= (a sin theta)sq + (a cos theta)sq

= a sq sin sq theta +a sq cos sq theta

=a sq (sin sq theta + cos sq theta)

= a sq ×1

= a sq Ans

Hope it helps

Answer 2

x =a sintheta & y = a cos theta  
x^2+ y^2 = a^2sin^2theta + a^2cos^2theta
= a^2(sin^2theta + cos^2theta)= a^2 ( 1) since sin^2theta + cos^2theta = 1
thus x^2 + y^2 = a^2.