The answer (Indefinite)
[src]
/ ___\
___ ____ |x*\/ 6 |
/ \/ 6 *\/ pi *S|-------|
| | ____|
| / 2\ \ \/ pi /
| sin\3*x / dx = C + -----------------------
| 6
/
$${{\sqrt{\pi}\,\left(\left(\sqrt{2}\,\sqrt{3}\,i+\sqrt{2}\,\sqrt{3}
\right)\,\mathrm{erf}\left({{\left(\sqrt{2}\,\sqrt{3}\,i+\sqrt{2}\,
\sqrt{3}\right)\,x}\over{2}}\right)+\left(\sqrt{2}\,\sqrt{3}\,i-
\sqrt{2}\,\sqrt{3}\right)\,\mathrm{erf}\left({{\left(\sqrt{2}\,
\sqrt{3}\,i-\sqrt{2}\,\sqrt{3}\right)\,x}\over{2}}\right)+\left(
\sqrt{2}\,\sqrt{3}-\sqrt{2}\,\sqrt{3}\,i\right)\,\mathrm{erf}\left(
\sqrt{3}\,\sqrt{-i}\,x\right)+\left(\sqrt{2}\,\sqrt{3}\,i+\sqrt{2}\,
\sqrt{3}\right)\,\mathrm{erf}\left(\left(-1\right)^{{{1}\over{4}}}\,
\sqrt{3}\,x\right)\right)}\over{48}}$$
/ ___ \
___ ____ |\/ 6 |
\/ 6 *\/ pi *S|------|*Gamma(3/4)
| ____|
\\/ pi /
---------------------------------
8*Gamma(7/4)
$${{\sqrt{\pi}\,\left(\left(\sqrt{2}\,\sqrt{3}\,i+\sqrt{2}\,\sqrt{3}
\right)\,\mathrm{erf}\left({{\sqrt{2}\,\sqrt{3}\,i+\sqrt{2}\,\sqrt{3
}}\over{2}}\right)+\left(\sqrt{2}\,\sqrt{3}\,i-\sqrt{2}\,\sqrt{3}
\right)\,\mathrm{erf}\left({{\sqrt{2}\,\sqrt{3}\,i-\sqrt{2}\,\sqrt{3
}}\over{2}}\right)+\left(\sqrt{2}\,\sqrt{3}-\sqrt{2}\,\sqrt{3}\,i
\right)\,\mathrm{erf}\left(\sqrt{3}\,\sqrt{-i}\right)+\left(\sqrt{2}
\,\sqrt{3}\,i+\sqrt{2}\,\sqrt{3}\right)\,\mathrm{erf}\left(\left(-1
\right)^{{{1}\over{4}}}\,\sqrt{3}\right)\right)}\over{48}}$$
=
/ ___ \
___ ____ |\/ 6 |
\/ 6 *\/ pi *S|------|*Gamma(3/4)
| ____|
\\/ pi /
---------------------------------
8*Gamma(7/4)
$$\frac{\sqrt{6} \sqrt{\pi} S\left(\frac{\sqrt{6}}{\sqrt{\pi}}\right) \Gamma\left(\frac{3}{4}\right)}{8 \Gamma\left(\frac{7}{4}\right)}$$