C crazylum New member Joined Apr 12, 2008 Messages 10 Apr 20, 2008 #1 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].
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].
D Deleted member 4993 Guest Apr 20, 2008 #2 crazylum said: 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]. Click to expand... (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 said: 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]. Click to expand... (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.
