Question

x=cosa 2y=sina;x+y=1.

Answer 1

x=cosa ,2y=sina

x²=cos²a,4y²=sin²a

x²+4y²=cos²a+sin²a=1

x+y=1,x=1-y

(1-y)²+4y²=1

5y²-2y=0

y(5y-2)=0

y1=0,y2=2/5

x1=1,x2=3/5