Name: Rain Xia       Student Number: 59118159

1. If part of the function is the derivate of another part of the function, we should use u-substitution to solve the problem.
2. If we see e^x, we should make e^x equals to u, because the derivate of e^x is itself.
3. Break the integral as small as possible. We can deal with smaller pieces each time in that way and we can use different substitution in different parts.