Integrand size = 18, antiderivative size = 85 \[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=-\frac {e^{-i c} \sqrt {\pi } \text {erfc}(b x)^2}{8 b}+\frac {e^{i c} \sqrt {\pi } \text {erfi}(b x)}{4 b}-\frac {b e^{i c} x^2 \, _2F_2\left (1,1;\frac {3}{2},2;b^2 x^2\right )}{2 \sqrt {\pi }} \]
-1/2*b*exp(I*c)*x^2*hypergeom([1, 1],[3/2, 2],b^2*x^2)/Pi^(1/2)-1/8*erfc(b *x)^2*Pi^(1/2)/b/exp(I*c)+1/4*exp(I*c)*erfi(b*x)*Pi^(1/2)/b
\[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=\int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx \]
Time = 0.49 (sec) , antiderivative size = 88, normalized size of antiderivative = 1.04, number of steps used = 7, number of rules used = 6, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.333, Rules used = {6962, 6928, 15, 6931, 2633, 6930}
Below are the steps used by Rubi to obtain the solution. The rule number used for the transformation is given above next to the arrow. The rules definitions used are listed below.
\(\displaystyle \int \text {erfc}(b x) \cos \left (c-i b^2 x^2\right ) \, dx\) |
\(\Big \downarrow \) 6962 |
\(\displaystyle \frac {1}{2} \int e^{-b^2 x^2-i c} \text {erfc}(b x)dx+\frac {1}{2} \int e^{b^2 x^2+i c} \text {erfc}(b x)dx\) |
\(\Big \downarrow \) 6928 |
\(\displaystyle \frac {1}{2} \int e^{b^2 x^2+i c} \text {erfc}(b x)dx-\frac {\sqrt {\pi } e^{-i c} \int \text {erfc}(b x)d\text {erfc}(b x)}{4 b}\) |
\(\Big \downarrow \) 15 |
\(\displaystyle \frac {1}{2} \int e^{b^2 x^2+i c} \text {erfc}(b x)dx-\frac {\sqrt {\pi } e^{-i c} \text {erfc}(b x)^2}{8 b}\) |
\(\Big \downarrow \) 6931 |
\(\displaystyle \frac {1}{2} \left (\int e^{b^2 x^2+i c}dx-\int e^{b^2 x^2+i c} \text {erf}(b x)dx\right )-\frac {\sqrt {\pi } e^{-i c} \text {erfc}(b x)^2}{8 b}\) |
\(\Big \downarrow \) 2633 |
\(\displaystyle \frac {1}{2} \left (\frac {\sqrt {\pi } e^{i c} \text {erfi}(b x)}{2 b}-\int e^{b^2 x^2+i c} \text {erf}(b x)dx\right )-\frac {\sqrt {\pi } e^{-i c} \text {erfc}(b x)^2}{8 b}\) |
\(\Big \downarrow \) 6930 |
\(\displaystyle \frac {1}{2} \left (\frac {\sqrt {\pi } e^{i c} \text {erfi}(b x)}{2 b}-\frac {b e^{i c} x^2 \, _2F_2\left (1,1;\frac {3}{2},2;b^2 x^2\right )}{\sqrt {\pi }}\right )-\frac {\sqrt {\pi } e^{-i c} \text {erfc}(b x)^2}{8 b}\) |
-1/8*(Sqrt[Pi]*Erfc[b*x]^2)/(b*E^(I*c)) + ((E^(I*c)*Sqrt[Pi]*Erfi[b*x])/(2 *b) - (b*E^(I*c)*x^2*HypergeometricPFQ[{1, 1}, {3/2, 2}, b^2*x^2])/Sqrt[Pi ])/2
3.3.2.3.1 Defintions of rubi rules used
Int[(a_.)*(x_)^(m_.), x_Symbol] :> Simp[a*(x^(m + 1)/(m + 1)), x] /; FreeQ[ {a, m}, x] && NeQ[m, -1]
Int[(F_)^((a_.) + (b_.)*((c_.) + (d_.)*(x_))^2), x_Symbol] :> Simp[F^a*Sqrt [Pi]*(Erfi[(c + d*x)*Rt[b*Log[F], 2]]/(2*d*Rt[b*Log[F], 2])), x] /; FreeQ[{ F, a, b, c, d}, x] && PosQ[b]
Int[E^((c_.) + (d_.)*(x_)^2)*Erfc[(b_.)*(x_)]^(n_.), x_Symbol] :> Simp[(-E^ c)*(Sqrt[Pi]/(2*b)) Subst[Int[x^n, x], x, Erfc[b*x]], x] /; FreeQ[{b, c, d, n}, x] && EqQ[d, -b^2]
Int[E^((c_.) + (d_.)*(x_)^2)*Erf[(b_.)*(x_)], x_Symbol] :> Simp[b*E^c*(x^2/ Sqrt[Pi])*HypergeometricPFQ[{1, 1}, {3/2, 2}, b^2*x^2], x] /; FreeQ[{b, c, d}, x] && EqQ[d, b^2]
Int[E^((c_.) + (d_.)*(x_)^2)*Erfc[(b_.)*(x_)], x_Symbol] :> Int[E^(c + d*x^ 2), x] - Int[E^(c + d*x^2)*Erf[b*x], x] /; FreeQ[{b, c, d}, x] && EqQ[d, b^ 2]
Int[Cos[(c_.) + (d_.)*(x_)^2]*Erfc[(b_.)*(x_)], x_Symbol] :> Simp[1/2 Int [E^((-I)*c - I*d*x^2)*Erfc[b*x], x], x] + Simp[1/2 Int[E^(I*c + I*d*x^2)* Erfc[b*x], x], x] /; FreeQ[{b, c, d}, x] && EqQ[d^2, -b^4]
\[\int \cos \left (i b^{2} x^{2}-c \right ) \operatorname {erfc}\left (b x \right )d x\]
\[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=\int { \cos \left (i \, b^{2} x^{2} - c\right ) \operatorname {erfc}\left (b x\right ) \,d x } \]
\[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=\int \cos {\left (i b^{2} x^{2} - c \right )} \operatorname {erfc}{\left (b x \right )}\, dx \]
\[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=\int { \cos \left (i \, b^{2} x^{2} - c\right ) \operatorname {erfc}\left (b x\right ) \,d x } \]
-1/8*sqrt(pi)*cos(c)*erfc(b*x)^2/b + 1/8*I*sqrt(pi)*erfc(b*x)^2*sin(c)/b + 1/2*cos(c)*integrate(erfc(b*x)*e^(b^2*x^2), x) + 1/2*I*integrate(erfc(b*x )*e^(b^2*x^2), x)*sin(c)
\[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=\int { \cos \left (i \, b^{2} x^{2} - c\right ) \operatorname {erfc}\left (b x\right ) \,d x } \]
Timed out. \[ \int \cos \left (c-i b^2 x^2\right ) \text {erfc}(b x) \, dx=\int \cos \left (c-b^2\,x^2\,1{}\mathrm {i}\right )\,\mathrm {erfc}\left (b\,x\right ) \,d x \]