Solving Integral from Table: Differences Explained

In summary, the conversation discusses an equation involving an integral in two different books. The first book presents the equation as \int \frac{1}{a^2-u^2}du=\frac{1}{2a} ln\left|\frac{u+a}{u-a}\right|+c, while the second book presents it as \int \frac{1}{a^2-u^2}du=\frac{1}{2a} \left(\int \frac{1}{a-u}du + \int \frac{1}{a+u}du\right) = \frac{1}{2a} \left(-ln\left| a-u \right|\right)+ln\left|
  • #1
Prologue
185
1
In a table in two different books they both say:
[tex]\int \frac{1}{a^2-u^2}du=\frac{1}{2a} ln\left|\frac{u+a}{u-a}\right|+c[/tex]

but I am not having the same result:

[tex]\int \frac{1}{a^2-u^2}du=\frac{1}{2a} \left(\int \frac{1}{a-u}du + \int \frac{1}{a+u}du\right) = \frac{1}{2a} \left(-ln\left| a-u \right|\right)+ln\left| a+u \right|+c = \frac{1}{2a} ln\left|\frac{a+u}{a-u}\right|+c[/tex]


Obviously the u+a at top is interchangeable but I am not seeing an explanation for the bottom (u-a vs. a-u) being different. Is it just an absolute value thing?
 
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  • #2
Well |a-u| = |u-a|, so yes I would say its just an absolute value thing.
 

1. What is an integral?

An integral is a mathematical concept that represents the area under a curve on a graph. It is used to find the total accumulation of a quantity over a certain interval.

2. How do I solve an integral using a table?

To solve an integral using a table, you need to first identify the function and limits of integration. Then, you can use a table of integrals to find the corresponding formula and plug in the limits to solve for the integral.

3. Why is it important to use a table when solving integrals?

A table of integrals provides a quick and easy reference for solving integrals. It can save time and reduce the likelihood of making calculation errors.

4. Can I solve any kind of integral using a table?

No, a table of integrals only contains the most common and basic integrals. For more complex integrals, you may need to use other methods such as integration by parts or substitution.

5. How do I know if I have solved an integral correctly?

You can check your answer by taking the derivative of your solution. If the derivative matches the original function, then your integral is solved correctly.

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