- #1
Fys
- 16
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I want to calculate the integral of a sphere with radius a using double integrals
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
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