✔ 最佳答案
When the curve of y = √(r2-x2) revolves around the x-axis, it generates a sphere with radius r. The volume =
V=π∫[from r to -r] (√(r2-x2))^2 dx=π∫[from r to -r] (r2-x2) dx=π(r^2x-x^3/3)[from r to -r]
=π(r^3-r^3/3+r^3-r^3/3)
=4/3πr^3
2006-12-13 18:08:06 補充:
A continuous function f(x) with positive images in interval [a,b], revolving around the x-axis, defines a volume π∫[from a to b] f(x)^2 dx上面應寫成(from -r to r)