# Thread: Intregation exponential square function

1. ## Intregation exponential square function

integrate(exp-(ax2+bx)/x wrt x where x range from 0 to 5*10-9

2. ## Re: Intregation exponential square function

First, you are missing a ")". Did you intend "integrate(exp-(ax2+bx)/x) wrt x"?

Second, it looks like that cannot be integrated in terms of "elementary functions". Do you want a numerical integration or integral in terms of the "error function"?

3. ## Re: Intregation exponential square function

yes I did miss a ) I tried error function exponential integral but all failed i just need a solution or an approximate solution to it for my research problem having Gaussian function

4. ## Re: Intregation exponential square function

Originally Posted by kamalakshabaral
yes I did miss a ) I tried error function exponential integral but all failed i just need a solution or an approximate solution to it for my research problem having Gaussian function
your notation is very unclear

do you mean to integrate $\dfrac{e^{-(ax^2 + b x)}}{x}$ ?

or do you mean $e^{-\dfrac{a x^2 + b x}{x}}$

if the first case the integral doesn't converge on $[0, 5\times 10^{-9}]$

if the second case why not write $e^{-(a x + b)}$ and the answer is

$\displaystyle \int_0^{5\times 10^{-9}}e^{-(ax + b)}~dx = \dfrac{\left(1-e^{-\frac{a}{200000000}}\right) e^{-b}}{a}$

5. ## Re: Intregation exponential square function

It's definitely not the second one ...........i have also got the result of non convergence in the above range ..........i am just wanting to know is there any other method to solve this.....

6. ## Re: Intregation exponential square function

Originally Posted by kamalakshabaral
It's definitely not the second one ...........i have also got the result of non convergence in the above range ..........i am just wanting to know is there any other method to solve this.....
what's to solve? It doesn't converge.

7. ## Re: Intregation exponential square function

but it can be solved numerically for certain values of constant a& b by applying taylor............

8. ## Re: Intregation exponential square function

"Does not converge" means that there is no number equal to that integral. If you are solving it numerically then your numerical method is giving a wrong answer!