1. The problem statement, all variables and given/known data Consider a large triangle, the tip is located at the origo x=0, it is sloped at an angle θ and -θ relative to the x-axis, relative to the x-axis, its dimensions in x can be considered infinite. A large stripe/strip/band is placed on top of the triangle but perpendicular to the x axis so to speak, it has a width b and it's center is located at x=0 and it can be considered infinite in the y direction. (So one edge of the stripe at the start is at x=b/2 and the other at x=-b/2.) This large stripe can be shifted in the x direction to gradually cover a larger and larger trapezoidal area of the triangle. The exercise is to find a generalised expression for the area shared by the triangle and the stripe as a function of x. 2. The attempt at a solution What I deduced was that this was a piecewise solution, while x<b/2 the area they share is: A(x)= tanθ(x+b/2)^2 (a basic area of a triangle, that gives it an area when x=0) And when x>b/2 it A(x)=1/2*b*(q+p) (the area of a trapezoid) Where q=2tanθ(x-b/2) and p=2tanθ(x+b/2) giving me a final expression in this part of: A(x)=2bx*tanθ Now my question is, the actual wording of the problem makes it sound like it should be possible to find one elegant expression covering the x>0 regardless of the zone, but I'm just completely lost in how one such might be found. Any help would be nice.