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If f(x) = x2 -1, what is the equation for f–1(x)?

User Eman
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1 Answer

1 vote

Answer:

Explanation:

That's f(x) = x^2 - 1, where the " ^ " indicates exponentiation.

To find the inverse function of f(x):

1. Replace "f(x)" with "y": y = x^2 - 1

2. Interchange x and y: x = y^2 - 1

3. Solve this result for y: y^2 = x + 1 or y = +√(x + 1).

Important: the inverse of the given function is defined only on the domain [-1, infinity), since the argument x + 1 MUST be ≤ 0. Also, because a relationship is a function ONLY if there is only 1 value of y for each value of x. That's why the inverse function is +√(x + 1) and not ±√(x + 1).

4. Finally, label the inverse function by replacing "y = " with

-1

"f (x) = ":

-1

f (x) = +√(x + 1)

User Bart Van Der Drift
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