I would like to be able to write my integrand before my integral and then have my integral be more compact. However Mathematica does not seem to like when I try and substitute in my dq's. Is there a way to tell mathematica to evaluate the substitution before evaluating the integral?(and, I guess, maintaining the order of my dq's, since I think mathematica would have a hard time parsing the integral if it assumes the dq's commute with the rest of the integrand)(adsbygoogle = window.adsbygoogle || []).push({});

This is what I'm trying to integrate:

[tex]\text{dg}\text{:=}G \rho /r`^2\ \text{dVol};\ \text{dVol}\text{:=}\sin [\theta ]\ r^2\ d\phi \ d\theta \ dr; \\g=\int _0^R\int _0^{\pi }\int _0^{2\pi }\text{dg} [/tex]

In case you're wondering, it's the gravitational field outside a uniform sphere.

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# Mathematica: Substituting in for integrand

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