I would like to solve the following integral
∫∞01t32e−aterf(√t)dt
with Re(a)>0 and erf the error function.
Is it possible to given an closed form solution for this integral? Thank you.
Edit: Maybe this helps
L(erf(√t),s)=1s√1+s
L−1(t−32e−at)=1√πasin(2√as)
with L the Laplace transform.
Therefore it should be
∫∞01t32e−aterf(√t)dt=∫∞01s√1+s√πasin(2√as)ds
Answer
Represent the erf as an integral and work a substitution. To wit, the integral is
2√π∫10dv∫∞0dtte−(a/t+v2t)
To evaluate the inner integral, we sub y=a/t+v2t. Then the reader can show that
∫∞0dtte−(a/t+v2t)=2∫∞2v√ady√y2−4av2e−y
The latter integral is easily evaluated using the sub y=2v√acoshw and is equal to
2∫∞2v√ady√y2−4av2e−y=2∫∞0dwe−2v√acoshw=2K0(2v√a)
where K0 is the modified Bessel function of the second kind of zeroth order. Now we integrate this expression with respect to v and multiply by the factors outside the integral to get the final result:
∫∞0dtt−3/2e−a/terf(√t)=4√π∫10dvK0(2v√a)=2√π[K0(2√a)L−1(2√a)+K1(2√a)L0(2√a)]
where L is a Struve function.
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