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Question
Select the correct answer from given alternatives.
If f : R → R is defined by f(x) = x3 then f–1 (8) is equal to :
Options
{2}
{–2, 2}
{–2}
(–2, 2)
Solution
{2}
Explanation;
f(x) = x3 = y, say
∴ x = `y^(1/3)` = f–1 (y)
∴ f–1 (8) = `(8)^(1/3) = (2^3)^(1/3)`
∴ f–1 (8) = {2}
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