Integrating Fractions: A Comprehensive Guide

Lodve
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I really struggle to integrate this fraction expression:


\int \frac{2}{4x^2+1}
 
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I presume you're familiar with the standard table of integrals?

http://www.maths.abdn.ac.uk/~igc/tch/ma1002/int/node51.html

Here's a list of many common ones, see if you can get it into the right form for one of them.

If you have to work this out by hand, consider using a trigonometric substitution, but choose carefully.

(Hint: the relationship 1 + x^2 = sec^2 for x = tan x)
 
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Yes, I'm fimiliar with some the of standard table of integrals. I think I just change the equation above in the form
\int \frac{1}{x^2+a^2} where a is an integer, so that the integration of the equation would likely be
\frac{1}{a} arctan(x/a)

But I'm not sure if I've done it right.
 


You chose the right one, try to get it into a form like that.
 


Thank you for helping me :D
 
Prove $$\int\limits_0^{\sqrt2/4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx = \frac{\pi^2}{8}.$$ Let $$I = \int\limits_0^{\sqrt 2 / 4}\frac{1}{\sqrt{x-x^2}}\arcsin\sqrt{\frac{(x-1)\left(x-1+x\sqrt{9-16x}\right)}{1-2x}} \, \mathrm dx. \tag{1}$$ The representation integral of ##\arcsin## is $$\arcsin u = \int\limits_{0}^{1} \frac{\mathrm dt}{\sqrt{1-t^2}}, \qquad 0 \leqslant u \leqslant 1.$$ Plugging identity above into ##(1)## with ##u...
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