Dien tich mat tron xoay do dien tich tao ra khi mot duong cong quay quanh truc.
Cong thuc chinh
Around x-axis: S = 2π integral y sqrt(1 + (dy/dx)2) dx
Around y-axis: S = 2π integral x sqrt(1 + (dx/dy)2) dy
Around y-axis: S = 2π integral x sqrt(1 + (dx/dy)2) dy
Vi du thuc te
Sphere check: rotating a semicircle of radius r gives S = 4πr2.
Tai nguyen lien quan
Use Sphere, Cylinder, Cone, and cone/frustum guide.