### Author Topic: Questions about Section 1.2 on page 11  (Read 1109 times)

#### Min Zhang

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##### Questions about Section 1.2 on page 11
« on: September 23, 2014, 06:32:35 PM »
I have been reading the textbook and found the following part that I don't quite understand:

At the top of page 11, it says

Quote
By the chain rule the left side of Eq. (6) is the derivative of ln|p-900| with respect to t, so we have  $d/dt\ ln|p-900| = 1/2$.

Then, by integrating both sides of Eq. (7), we obtain  $\ln|p-900| = t/2+C$

So my questions are:

1. Why can we get those statements?

2. Why do we have to insert a constant number $C$?

Thank you very much!
« Last Edit: September 23, 2014, 11:23:09 PM by Victor Ivrii »