Quote:
Originally Posted by Strive_Do IT
If X^2 + Y^2 = 1, is X + Y = 1?
(1) XY = 0
(2) Y = 0
Pls provide explanation on how to work this problem out.
Thanks,
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Wow, I'm out of it today...
1. If XY = 0, then either x or y is zero. Both can't be zero though, since X^2 + Y^2 = 1.
So, either x^2 = 1 or y^2 = 1, which allows for x or y to be -1 or 1. So, X+Y can be either 1 or -1.
INSUFFICIENT
2. We already covered this in part 1. If y = 0 then x can be 1 or -1.
INSUFFICIENT
E