Wednesday, February 3, 2010
GMAT Question of the day
If (a + 1/a)^2 = 3, then a^3 + 1/a^3 equals
(a) 0
(b) 3√3
(c) 10√3/3
(d) 6√3
(a + 1/a)^2 = 3 or (a + 1/a) = 3^(1/2) and we know that
(a + 1/a)^3 = a^3 + 1/a^3 + 3(a + 1/a)
⇒ (a3 +1/a3) = 3√ 3 – 3/3 = 0
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