by Regulus » October 18th, 2013, 5:53 pm
This stuff is confusing. Not that it's difficult to conceptualize, it's just tricky not to make a mistake with so much going on. Gradients, tangent planes, normal lines in parametric form, normal lines in symmetrical form, tangent lines in parametric form, tangent lines in symmetrical form, angles of inclination, angles of intersecting planes, lines tangent to intersecting planes tangent to surfaces at points, lines normal to intersecting planes tangent to surfaces at points--it all starts to get mixed up after a few computations.