I'm trying to calculate the area of intersection of a cone and a disk which is a circular slice of the cone rotated through a particular angle about the apex of the cone. I've defined the cone using a set of inequalities with ImplicitRegion and have found a parametrization for the circle. I'm confident I have found the right equations because plotting RegionUnion produces what I expect to see, for example for the disk rotated through 1 degree:
R = 1.4; d = 30; T = Pi/180; cone = ImplicitRegion[{x^2 + y^2 <= (z Tan[R/d])^2,0 <= z < 1.2*d}, {x, y, z}]; disk = ParametricRegion[{d Sin[T] - r Cos[T] Cos[t], r Sin[t],d Cos[T] - r Cos[t] Sin[T]}, {{r, 0, 1.42}, {t, 0, 2 Pi}}]; Region[cone] Region[disk] Region[RegionUnion[cone, disk]] However, I can't get it to plot the intersection or calculate the area of the intersection:
Region[RegionIntersection[cone, disk]] produces the output
and asking it for the area of intersection,
Area[RegionIntersection[cone, disk]] Can anyone help me figure out why this isn't working and how to calculate the area of intersection?




