Question

Which one of the following function is not invertible?

• A. $f:R\to R,f\left(x\right)=3x+1$
• B. $f:R\to [0,\infty ),f\left(x\right)=x^2$
• C. $f:R^{+}\to R^{+},f\left(x\right)=\frac{1}{x^3}$
• D. $Noneoftheabove$

Answer 1

The correct option is B $f:R\to [0,\infty ),f\left(x\right)=x^2$

The function f(x) = $x^2$, x $ϵ$R is not one – one because
f(-4)=f (4) = 16
$\therefore$ It is not invertible