var('p t')spherical_plot3d(2,(t,0,pi),(p,0,3*pi/4))# The Sage default has rho(theta, phi):
# We can also use a "transformation"var('rho theta phi')spherical=(rho*sin(phi)*cos(theta),rho*sin(phi)*sin(theta),rho*cos(phi))plot3d(2,(theta,0,pi),(phi,0,3*pi/4),transformation=spherical)