\[ \int \sec ^{\frac {7}{2}}(a+b x) \, dx \]
Optimal antiderivative \[ \frac {2 \left (\sec ^{\frac {5}{2}}\left (b x +a \right )\right ) \sin \left (b x +a \right )}{5 b}+\frac {6 \sin \left (b x +a \right ) \left (\sqrt {\sec }\left (b x +a \right )\right )}{5 b}-\frac {6 \sqrt {\frac {\cos \left (b x +a \right )}{2}+\frac {1}{2}}\, \EllipticE \left (\sin \left (\frac {a}{2}+\frac {b x}{2}\right ), \sqrt {2}\right ) \left (\sqrt {\cos }\left (b x +a \right )\right ) \left (\sqrt {\sec }\left (b x +a \right )\right )}{5 \cos \left (\frac {a}{2}+\frac {b x}{2}\right ) b} \]
command
integrate(sec(b*x+a)^(7/2),x, algorithm="fricas")
Fricas 1.3.8 (sbcl 2.2.11.debian) via sagemath 9.6 output
\[ \frac {-3 i \, \sqrt {2} \cos \left (b x + a\right )^{2} {\rm weierstrassZeta}\left (-4, 0, {\rm weierstrassPInverse}\left (-4, 0, \cos \left (b x + a\right ) + i \, \sin \left (b x + a\right )\right )\right ) + 3 i \, \sqrt {2} \cos \left (b x + a\right )^{2} {\rm weierstrassZeta}\left (-4, 0, {\rm weierstrassPInverse}\left (-4, 0, \cos \left (b x + a\right ) - i \, \sin \left (b x + a\right )\right )\right ) + \frac {2 \, {\left (3 \, \cos \left (b x + a\right )^{2} + 1\right )} \sin \left (b x + a\right )}{\sqrt {\cos \left (b x + a\right )}}}{5 \, b \cos \left (b x + a\right )^{2}} \]
Fricas 1.3.7 via sagemath 9.3 output
\[ {\rm integral}\left (\sec \left (b x + a\right )^{\frac {7}{2}}, x\right ) \]