### Home > CALC > Chapter 1 > Lesson 1.4.2 > Problem 1-160

1-160.

The function

*y*=*x*^{3}+ 1 is graphed below, along with four left endpoint rectangles which approximate the area from*x*= −2 to*x*= 2. Homework Help ✎

Why does it look like there are only three rectangles?

Recall that area under the

*x*-axis is negative, while that above the*x*-axis is positive. Approximate*A*(*y*, −2 ≤*x*≤ 2) using these four rectangles.

What happens if the left endpoint is on the *x*-axis?

Since *f*(−1) = 0, the height of the rectangle is 0.

Sum the areas of all four rectangles together. Remember to treat a rectangle's area as negative if it is below the *x*-axis.