### Home > CALC > Chapter 1 > Lesson 1.3.3 > Problem1-125

1-125.

Carefully graph the function $f ( x ) = \left\{ \begin{array} { c c } { 3 x + 4 } & { \text { for } x < 1 } \\ { - \frac { 1 } { 2 } x + 5.5 } & { \text { for } x \geq 1 } \end{array} \right.$ .

1. Iveta wants to find $A(f(x)$, $-1 ≤ x ≤ 5$), so she decided to split the region into $10$ trapezoids and approximate the area. Explain to Iveta why this is not the most efficient method.

Can you find a way to calculate the area accurately with less than $10$ trapezoids?

Because the function is composed of two linear pieces, the exact area can be computed using two trapezoids.

2. Calculate $A(f(x)$, $-1 ≤ x ≤ 5$).

Use the eTool below to visualize this problem.
Click the link at right for the full version of the eTool: Calc 1-125 HW eTool