Linked Questions
18 questions linked to/from Integral of $\frac{1}{(1+x^2)^2}$
10 votes
3 answers
4k views
Some method to solve $\int \frac{1}{\left(1+x^2\right)^{2}} dx$ and some doubts. [duplicate]
First approach. $\int \frac{1}{1+x^2} dx=\frac{x}{1+x^2}+2\int \frac{x^2}{\left(1+x^2\right)^2} dx=\frac{x}{1+x^2}+2\int \frac{1}{1+x^2}dx-2\int \frac{1}{\left(1+x^2\right)^2}dx$ From this ...
3 votes
8 answers
2k views
Evaulating the trigonometric integral $\int \frac{1}{(x^2+1)^2} \, dx$ [duplicate]
Problem: Evaluate the following integral: \begin{eqnarray*} \int \frac{1}{(x^2+1)^2} \, dx \\ \end{eqnarray*} Answer: To do this, I let $x = \tan u$. Now we have $dx = \sec^2 u du$. \begin{eqnarray*} \...
3 votes
5 answers
312 views
Can you solve $\int 1/(x^2+1)^2\, dx$ [duplicate]
I know that the integral looks like like the anti-derivative of $\arctan$, but i don't know how to use this fact so I tried to use a fraction decomposition to: $$\frac{1}{(x^2+1)^2}$$ to solve the ...
3 votes
6 answers
933 views
How to simplify the integral $\int \frac{1}{(1+x^2)^2}dx$? [duplicate]
If any integration is in form $$\int \frac{1}{1+x^2}dx$$ it easily follows by substituting for $\tan^{-1}x$. But how to simplify if we have $$\int \frac{1}{(1+x^2)^2}dx$$
2 votes
3 answers
203 views
How to compute $\int \frac{1}{(x^2+1)^2}dx$? [duplicate]
Suppose we know $\int \frac{1-x^2}{(x^2+1)^2}=\frac{x}{x^2+1}+C$ How to compute $\int \frac{1}{(x^2+1)^2}dx$? I tried writing it as $\frac{1+x^2-x^2}{(x^2+1)^2}=\frac{1-x^2}{(x^2+1)^2}+\frac{x^2}{(x^...
2 votes
3 answers
123 views
How to solve this integration that I got from differential linear equation? [duplicate]
I worked differential linear equation and at end of equation I got this integral.Can someone give me a hint to do this: $$\int \frac{1}{\left(u^2+1\right)^2}du$$
0 votes
3 answers
246 views
How to solve for integral $\int \frac{dx}{\left(x^2+4\right)^2}$ [duplicate]
How to solve for: $\int \frac{dx}{\left(x^2+4\right)^2}$ What I have tried so far: Let $x = 2 \tan \theta$ so that $dx = 2 \sec^2\theta d\theta$ $I = \int \frac{2 \sec^2 \theta d\theta}{\left(16 ...
2 votes
4 answers
196 views
$\int\frac1{(x^2+1)^2}\ dx$ by partial fraction decomposition [duplicate]
Is there any possible way to calculate the integral of $\frac{1}{(x^2+1)^2}$ by partial fraction decomposition? I do not know the formulas for the trigonometric method. Thank you!
59 votes
3 answers
4k views
Making trigonometric substitutions rigorous
I've been tutoring some basic calculus, and it made me think about something pretty basic. Let me explain the problem by example: Say we are given the integral $\int \frac{x^2}{\sqrt{1-x^2}}\ \...
14 votes
1 answer
16k views
Recurrence relation for the integral, $ I_n=\int\frac{dx}{(1+x^2)^n} $
Express recurrence relation of the integral $$ I_n=\int\frac{dx}{(1+x^2)^n} $$ [My Answer] $$ I_n = \int\frac{1+x^2}{(1+x^2)^n}dx-\int\frac{x^2}{(1+x^2)^n}dx $$ $$ I_n=I_{n-1}-\int x\cdot\frac{x}{...
5 votes
4 answers
465 views
partial fractions when the fraction cannot be decomposed
I am trying to find partial fractions of $\frac {1}{(x^2+1)^2}$. All the coefficients I get are zeros except the coefficient for the constant term which is 1, leaving me with the fraction I started ...
7 votes
8 answers
280 views
Indefinite integral $\int \frac{1-x}{\sqrt{1+x-2x^2}}\,dx $
For my engineering math course I got a couple of exercises about indefinite integrals. I ran trought all of them but stumbled upon the following problem. $$\int \frac{1-x}{\sqrt{1+x-2x^2}}\,dx $$ ...
6 votes
3 answers
230 views
Integrating a Rational Function
I am studying for a test and I am trying to evauate the integral below. I know how to simplify it with partial fractions, but when I try to solve it, I cannot seem to find a substitution that will ...
2 votes
2 answers
282 views
What is the easiest way to integrate $y=\frac {x+4}{\sqrt{-x^2-2x+3}}$?
What is the easiest way to integrate $y=\frac{x+4}{\sqrt{-x^2-2x+3}}$ ? I tried to integrate it by making numerator in form: $-2x-2$ and then pulling it under differential, but the result drastically ...
1 vote
4 answers
232 views
Evaluate $\int \frac{1}{(x^2+1)^2}dx$ [closed]
$$\int \frac{1}{(x^2+1)^2}\mathrm dx$$ Look simple, but I stuck a little bit. What method is better in this situation? Please, help.