CPM Homework Banner

The function is graphed at right, along with four left endpoint rectangles which approximate the area under the curve from to .

  1. Why does it look like there are only three rectangles?

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

    Since , the height of the rectangle is .

  2. Recall that area under the -axis is negative, while area above the -axis is positive. Approximate the area under the curve for using these four rectangles.

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