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I am trying to understand calculus as concerns circles and I can clearly see that the integral of a circumference is an area:

[itex]\int2∏r[/itex] = ∏r[itex]^{2}[/itex]

but what do I get if I integrate the area, I get

∏r[itex]^{3}[/itex]/3

I am confused as to what this shape would be, I kind of was expecting a sphere, but the formula for a sphere is:

4∏r^{3}/3

plus a little technical point: when differentiating this, is it dr/dx or dy/dr, or am I totally off the mark?

Thanks in advance

Rob K

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# Integration of circle

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