Given xy=1 , x^2+y^2=2 , find the value of x+y .

Question

Given xy=1 , x^2+y^2=2 , find the value of x+y .

Collected in the board: Perfect square polynomials

Steven Zheng posted 3 years ago

Answer

(x+y)^2 = x^2+y^2+2xy = 2+2 = 4

Therefore,

x+y = \pm2

Steven Zheng posted 3 years ago