But, basically you don't really need to remember these formulas as long as you remember how to express r in terms of rho sine phi, and x equals r cos theta.
事实上你不用记住这些公式,只需要知道r=ρ*sinφ,而x=r*cosθ
2
Don't get things mixed up, just the z component of the force becomes Gm triple integral of delta cos phi sine phi d rho d phi d theta.