I'll show you how to do #7. The following questions can be done by the same method:

is to be approximated by 2 stripes:

1. Divide the interval [0, 2] into 2 equal parts: [0, 1], (1, 2]. The length of each part is 1.

2. Calculate

3. Calculate the area of the 2 trapezoids:

Since the upper border of the trapezoids is allways above the curve this value must be slightly too large.

4. The exact value is