Integral de x^3sqrt(1+9x^2) dx

TrigSubstitutionRule(theta=_theta, func=tan(_theta)/3, rewritten=sin(_theta)**3/(81*cos(_theta)**6), substep=ConstantTimesRule(constant=1/81, other=sin(_theta)**3/cos(_theta)**6, substep=RewriteRule(rewritten=(1 - cos(_theta)**2)*sin(_theta)/cos(_theta)**6, substep=AlternativeRule(alternatives=[URule(u_var=_u, u_func=cos(_theta), constant=1, substep=RewriteRule(rewritten=_u**(-4) - 1/_u**6, substep=AddRule(substeps=[PowerRule(base=_u, exp=-4, context=_u**(-4), symbol=_u), ConstantTimesRule(constant=-1, other=_u**(-6), substep=PowerRule(base=_u, exp=-6, context=_u**(-6), symbol=_u), context=-1/_u**6, symbol=_u)], context=_u**(-4) - 1/_u**6, symbol=_u), context=(_u**2 - 1)/_u**6, symbol=_u), context=(1 - cos(_theta)**2)*sin(_theta)/cos(_theta)**6, symbol=_theta), RewriteRule(rewritten=-(sin(_theta)*cos(_theta)**2 - sin(_theta))/cos(_theta)**6, substep=ConstantTimesRule(constant=-1, other=(sin(_theta)*cos(_theta)**2 - sin(_theta))/cos(_theta)**6, substep=AlternativeRule(alternatives=[URule(u_var=_u, u_func=cos(_theta), constant=-1, substep=ConstantTimesRule(constant=-1, other=(_u**2 - 1)/_u**6, substep=RewriteRule(rewritten=_u**(-4) - 1/_u**6, substep=AddRule(substeps=[PowerRule(base=_u, exp=-4, context=_u**(-4), symbol=_u), ConstantTimesRule(constant=-1, other=_u**(-6), substep=PowerRule(base=_u, exp=-6, context=_u**(-6), symbol=_u), context=-1/_u**6, symbol=_u)], context=_u**(-4) - 1/_u**6, symbol=_u), context=(_u**2 - 1)/_u**6, symbol=_u), context=(_u**2 - 1)/_u**6, symbol=_u), context=(sin(_theta)*cos(_theta)**2 - sin(_theta))/cos(_theta)**6, symbol=_theta), RewriteRule(rewritten=sin(_theta)/cos(_theta)**4 - sin(_theta)/cos(_theta)**6, substep=AddRule(substeps=[URule(u_var=_u, u_func=cos(_theta), constant=-1, substep=ConstantTimesRule(constant=-1, other=_u**(-4), substep=PowerRule(base=_u, exp=-4, context=_u**(-4), symbol=_u), context=_u**(-4), symbol=_u), context=sin(_theta)/cos(_theta)**4, symbol=_theta), ConstantTimesRule(constant=-1, other=sin(_theta)/cos(_theta)**6, substep=URule(u_var=_u, u_func=cos(_theta), constant=-1, substep=ConstantTimesRule(constant=-1, other=_u**(-6), substep=PowerRule(base=_u, exp=-6, context=_u**(-6), symbol=_u), context=_u**(-6), symbol=_u), context=sin(_theta)/cos(_theta)**6, symbol=_theta), context=-sin(_theta)/cos(_theta)**6, symbol=_theta)], context=sin(_theta)/cos(_theta)**4 - sin(_theta)/cos(_theta)**6, symbol=_theta), context=(sin(_theta)*cos(_theta)**2 - sin(_theta))/cos(_theta)**6, symbol=_theta)], context=(sin(_theta)*cos(_theta)**2 - sin(_theta))/cos(_theta)**6, symbol=_theta), context=-(sin(_theta)*cos(_theta)**2 - sin(_theta))/cos(_theta)**6, symbol=_theta), context=(1 - cos(_theta)**2)*sin(_theta)/cos(_theta)**6, symbol=_theta), RewriteRule(rewritten=-sin(_theta)/cos(_theta)**4 + sin(_theta)/cos(_theta)**6, substep=AddRule(substeps=[ConstantTimesRule(constant=-1, other=sin(_theta)/cos(_theta)**4, substep=URule(u_var=_u, u_func=cos(_theta), constant=-1, substep=ConstantTimesRule(constant=-1, other=_u**(-4), substep=PowerRule(base=_u, exp=-4, context=_u**(-4), symbol=_u), context=_u**(-4), symbol=_u), context=sin(_theta)/cos(_theta)**4, symbol=_theta), context=-sin(_theta)/cos(_theta)**4, symbol=_theta), URule(u_var=_u, u_func=cos(_theta), constant=-1, substep=ConstantTimesRule(constant=-1, other=_u**(-6), substep=PowerRule(base=_u, exp=-6, context=_u**(-6), symbol=_u), context=_u**(-6), symbol=_u), context=sin(_theta)/cos(_theta)**6, symbol=_theta)], context=-sin(_theta)/cos(_theta)**4 + sin(_theta)/cos(_theta)**6, symbol=_theta), context=(1 - cos(_theta)**2)*sin(_theta)/cos(_theta)**6, symbol=_theta)], context=(1 - cos(_theta)**2)*sin(_theta)/cos(_theta)**6, symbol=_theta), context=sin(_theta)**3/cos(_theta)**6, symbol=_theta), context=sin(_theta)**3/(81*cos(_theta)**6), symbol=_theta), restriction=True, context=x**3*sqrt(9*x**2 + 1), symbol=x)

1. Ahora simplificar:

   $\frac{\left(9 x^{2} + 1\right)^{\frac{3}{2}} \left(27 x^{2} - 2\right)}{1215}$

2. Añadimos la constante de integración:

   $\frac{\left(9 x^{2} + 1\right)^{\frac{3}{2}} \left(27 x^{2} - 2\right)}{1215}+ \mathrm{constant}$

Respuesta:

$\frac{\left(9 x^{2} + 1\right)^{\frac{3}{2}} \left(27 x^{2} - 2\right)}{1215}+ \mathrm{constant}$