Question

Show that the function $f:R\to R$ defined as $f\left(x\right)=x^2$, is not one-one.

Answer 1

Given the function $f:R\to R$ defined as $f\left(x\right)=x^2$.

Now we have $2,-2\in R$ but $f\left(2\right)=f(-2)=4$.

This gives that the function $f\left(x\right)$ is not one-one.