1. Calculator can help people nd out the answer to the integral quickly and with convenience. However. we can't only depend on the calculator; understanding the technique ion the chapter can give students a deep understanding of calculus and it characteristics. This will be very useful for students to learn. Another reason is that we may not have access to this kind of calculator in any situation, and sometimes the calculator canl not give us the correct answer. That is why we need to learn techniques in this section. 2. One example of using integration in my major area is calculating the result of acoustic measurement. In acoustic measurement, we generate a sound source like the sin sweeps wave to make the impulse response measurement. A very basic and signicant part of analyzing the result of the measurement data is to generate the energy decay curve from the data we measured.Then we need to use integration. 1 .f E(!)= Jp2(1)dr= Jp2fr) (Elfr) r