Integrate the following using Partial Fractions. \int \frac{xdx}{x^2-3x-4}

Roger Smith

Roger Smith

Answered question

2021-12-17

Integrate the following using Partial Fractions.
xdxx23x4

Answer & Explanation

zesponderyd

zesponderyd

Beginner2021-12-18Added 41 answers

Given: xdxx23x4
To Find- The value of the above integration using partial fractions.
Explanation- Rewrite the given expression as,
I=xdxx23x4
Now, simplifying the above expression as follows,we get,
=xdxx44x+x4
=x(x+1)(x4)dx
The above expression can be simplified using partial fractions, we get,
x(x+1)(x4)=A(x+1)+B(x4)(1)
x(x+1)(x4)=A(x4)+B(x+1)(x+1)(x4)
x=A(x4)+B(x+1)
To Find the value of A and B, we have to substitute the value of x as 4 in the above expression, we get,
4=0+5B
Further, we can write as follows,
B=45
Similarily, substituting the value of x as -1 in the above expression, we get,
A=15
So, the equation (1) can be written as follows,
x(x+1)(x4)=151(x+1)dx+451(x4)dx
=15ln|x+1|+45ln|x4|+C
Answer- Hence, the solution of the integral xdxx23x4  is  15ln|x+1|+45ln|x4|+C
kaluitagf

kaluitagf

Beginner2021-12-19Added 38 answers

xx23x4dx
Take the partial fractions of : xx23x4:15(x+1)+45(x4)
=15(x+1)+45(x4)dx
Apply the Sum Rule: f(x)±g(x)dx=f(x)dx±g(x)dx
=15(x+1)dx+45(x4)dx
15(x+1)dx=15ln|x+1|
45(x4)dx=45ln|x4|
=15ln|x+1|+45ln|x4|
Solution:
=15ln|x+1|+45ln|x4|+C
RizerMix

RizerMix

Expert2021-12-29Added 656 answers

I have been looking for this solution for so long, please help me

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