If (x + 1/x)2 = 3, find x3 + 1/x3.
Answer :
It is given that
(x + 1/x)2 = 3
(x + 1/x) = ± √3
We know that
x3 + 1/x3 = (x + 1/x)3 – 3 (x + 1/x)
Substituting the values
x3 + 1/x3 = (± √3)3 – 3 (± √3)
By further calculation
x3 + 1/x3 = (± 3√3) – (± 3√3) = 0
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