Integration problems

[shaidul]

Hello,

I need help from someone who is good at solving integration problems. This is the problem ∫ ( x^2) / √(4 - x^2) dx
Please post the steps on how to solve this problem with the answer.

[Timster]

Integrate (x^2/ (x^2 + 4)) dx = Integrate (1 - 4/ (x^2 + 4)) dx =x - 2arctan(x/2) + c

[shaidul]

@Timster, this is a trignometric substitution problem and so the correct answer from a website is 2 arcsin(x/2)-1/2*x*sqrt(4-x^2)+c.
Please redo the problem and show the steps.

[Timster]

(11-13-2015, 04:35 PM)shaidul Wrote:  @Timster, this is a trignometric substitution problem and so the correct answer from a website is 2 arcsin(x/2)-1/2*x*sqrt(4-x^2)+c.
Please redo the problem and show the steps.

That's why that answer is wrong... You got it from a website.

[shaidul]

The same answer is written in the textbook also.

[Britec]

You can use sites like this to solve you're trigonometry problem, there is loads of site that can help you solve this.

https://www.freemathhelp.com/trigonometry-help.html

[Timster]

That's where I got my answer.