I want to calculate the integral of a sphere with radius a using double integrals(adsbygoogle = window.adsbygoogle || []).push({});

I have [tex] z^2+y^2+x^2=a [/tex] and I plug this in my equation and integrate in polar coördinates

Now i have [tex] \int^{2\pi}_{0} \int ^{a}_{0} \sqrt{(a-r^{2})} rdrd\theta [/tex]

But why do I need to multiply my integral with 2 (because i get half the answer I expect).

Can someone explain this please?

thanks guys

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Double integration calculation

**Physics Forums | Science Articles, Homework Help, Discussion**