Question

For all real values of $x$, increasing function $f\left(x\right)$ is

• A. $x^{-1}$
• B. $x^2$
• C. $x^3$
• D. $x^4$

Answer 1

The correct option is C

$x^3$

Finding the value of the given function:

Take $f\left(x\right)=x^3$

Now, differentiate with respect to $x$. we get

$f\text{'}\left(x\right)=3x^2$

It is non negative for real values of $x$.

Thus, $f\left(x\right)=x^3$ is an increasing function.

Hence, option C is correct .