## Precalculus: Concepts Through Functions, A Unit Circle Approach to Trigonometry (3rd Edition)

$$6$$
Our aim is to calculate the approximation of $A$, the area under the function using the right endpoints. We are given that the length of each sub-interval is $1$. Therefore we have: $$A=(2-1)f(2)+(3-2)f(3) \\=f(2)+f(3)\\=2+4 \\ =6$$