Sunday, September 29, 2019

calculus - Evaluating $ int_{-infty}^{infty}xexpleft(-b^{2}left(x-cright)^{2}right)mathrm{erf}^{2}left(aleft(x-dright)right),mathrm{d}x $

I have big difficulties solving the following integral:

$$
\int_{-\infty}^{\infty}x\exp\left(-b^{2}\left(x-c\right)^{2}\right)\mathrm{erf}^{2}\left(a\left(x-d\right)\right)\,\mathrm{d}x
$$



I tried to use integration by parts, and also tried to apply the technique called “differentiation under the integration sign” but with no results.



I’m not very good at calculus so my question is if anyone could give me any hint of how to approach this integral. I would be ultimately thankful.



If it could help at all, I know that
$$

\int_{-\infty}^{\infty}x\exp\left(-b^{2}\left(x-c\right)^{2}\right)\mathrm{erf}\left(a\left(x-d\right)\right)\,\mathrm{d}x=\frac{a}{b^{2}\sqrt{a^{2}+b^{2}}}\exp\left(-\frac{a^{2}b^{2}\left(c-d\right)^{2}}{a^{2}+b^{2}}\right)+\frac{\sqrt{\pi}c}{b}\mathrm{erf}\left(\frac{ab\left(c-d\right)}{\sqrt{a^{2}+b^{2}}}\right),
$$



for $b>0$.

No comments:

Post a Comment

analysis - Injection, making bijection

I have injection $f \colon A \rightarrow B$ and I want to get bijection. Can I just resting codomain to $f(A)$? I know that every function i...