Question Details

Let function R → R is defined as f(x) = 2x³ – 1, then ‘f’ is

Options

A

2x³ + 1

B

(2x)³ + 1

C

(1 – 2x)³

D

[(1+x)/2]¹/³

Correct Answer :

[(1+x)/2]¹/³

Solution :

The correct option is [(1+x)/2]¹/³ .

To determine the inverse of the given function, we need to express the variable x in terms of y.

Let the given function be represented as:

y = f ( x ) = 2 x 3 1

Now, we solve for x step-by-step:

First, add 1 to both sides of the equation:

y + 1 = 2 x 3

Next, divide both sides by 2 to isolate the cubic term:

x 3 = y + 1 2

To solve for x, take the cube root of both sides of the equation:

x = y + 1 2 1 / 3

Since y=f(x), we have x=f1(y). Substituting this gives:

f 1 ( y ) = 1 + y 2 1 / 3

Replacing the dummy variable y with x to write it in standard function notation, we obtain the inverse function:

f 1 ( x ) = 1 + x 2 1 / 3

Therefore, the inverse function of f is indeed 1+x21/3.

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