If X and y satisfy the realation x-1)^2+y^2 is equal to 1 then possible value of X+y is equal to?

1 Answer
Jun 5, 2018

x+y=1+cosθ+sinθ for θ[0,2π]
Possible value: x+y=2;θ=0

Explanation:

(x1)2+y2=1

f(x,y) above is a unit circle centered at the point (1,0)

Now, consider a point P on the circle making an angle θ with the xaxis at the point (1,0)

By definition,

the y-component of P is sinθ
the x-component of P is 1+cosθ

Now, P can move around the circle as θ[0,2π]

Hence, x+y=1+cosθ+sinθ for θ[0,2π]

Since we are asked to find a "possible" value of x+y

Let θ=0x+y=1+1+0=2
which is of course the diameter of the circle.