Question

Which of the following functions is non – injective?

• A. $f\left(x\right)=|x+1|,xϵ[-1,\infty )$
• B. $g\left(x\right)=x+\frac{1}{x},xϵ(0,\infty )$
• C. $h\left(x\right)=x^2+4x-5,xϵ(1,\infty )$
• D. $k\left(x\right)=e^{-x},xϵ[0,\infty )$

Answer 1

The correct option is B $g\left(x\right)=x+\frac{1}{x},xϵ(0,\infty )$

Clearly, (a) Increasing.
(b) Neither increasing nor decreasing
(c) Increasing
(d) Decreasing