Question

( lambda+y=3-cos 40 quad x-y=4 sin 20 )
( (x+y-3)=-cos 40 quadleft(frac{x-y}{4}right)=sin 20 )
( cos 40=quad 1-2 sin ^{2} 20 )
( -(x+y-3)=1-2left(frac{x-y}{4}right)^{2} )
( -2 x-2 y+6 )
( =2-(x-y)^{2} )
( 2 x-2 y+6=2-x^{2}-y^{2}+2 x y )
( x^{2}+y^{2}-2 x-2 y-2 x y+4=0 )
( (x-1)^{2}+(y-1)^{2}+2-2 x y=0 )
is Conert ( x=y=1 )
50
( mathcal{D} )

# If x+y= 3 - cos40 (A) x4 + y4 = 9 and x-y= 4 sin20 then add both (B) Vx+Vy=16 (C) x3 + y) = 2(x2 + y2) (D) x + Vy=2

Solution