The element of volume delta V of the right circular cone of altitude h and base radius r is formed by slicing the cone at a distance x from the vertex. if the slice is finite thickness delta x, show that its delta v is [pi*r^2/h^2][x^2*deltax+x(deltax)^2+1/3(deltax)^3]. Explain what happens to second and third terms when deltax becomes the infinitesimal dx