Suppose x + y = 1, x^2 + y^2 = 4. Evaluate x^3 + y^3.

[crazylum]

Suppose x+y=1 and x[sup:2ed78dc6]2[/sup:2ed78dc6]+y[sup:2ed78dc6]2[/sup:2ed78dc6]=4. Evaluate x[sup:2ed78dc6]3[/sup:2ed78dc6]+y[sup:2ed78dc6]3[/sup:2ed78dc6].

 

[Deleted member 4993]

Suppose x+y=1 and x[sup:wws3vn3w]2[/sup:wws3vn3w]+y[sup:wws3vn3w]2[/sup:wws3vn3w]=4. Evaluate x[sup:wws3vn3w]3[/sup:wws3vn3w]+y[sup:wws3vn3w]3[/sup:wws3vn3w].

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

1 = 4+2xy

xy = -3/2

(x^3 + y^3) = (x+y)(x^2 + y^2 -xy)................(1)

You know all the terms of right-hand-side of equation(1) - evaluate.

 

[crazylum]

THANK YOU!!!!!!!!