# Ques 13 could you please help?

Dec 8, 2017

The answer is D.

#### Explanation:

A. Incorrect. The "image set" refers to the entire domain of $f \left(x\right)$. Option A describes the range.

B. Incorrect. This wrongly uses interval notation do describe the domain by including 4 in the interval. The domain of $f \left(x\right)$ is $\left[1 , 4\right)$, not $\left[1 , 4\right]$.

C. Incorrect. As $f$ increases, then decreases within the interval from #(1,3).

D. Correct. We can see from the graph that $f$ is decreasing from 2 to 3.

E. Incorrect. If we graph the inverse of $f \left(x\right)$ by reflecting $f \left(x\right)$ over $y = x$ (or imagining the graph), ${f}^{-} 1 \left(x\right)$ does not pass the vertical line test.