Previous Year Paper
CAT-2002-Previous Years Paper
If x, y and z are real numbers such that x + y + z = 5 and xy + yz + zx = 3, what is the largest value that x can have?
|D||None of these|
(x + y + z)2= x2+ y2+ z2+ 2 (xy + zy + zx)
⇒x2+ y2+ z2= 19
⇒y + z cannot be simultaneously = 0 else xy+zy+zx=0 ⇒ x2<19 ⇒ x<≅ 4.4