See section 12.13.10 for checking for isosceles triangles in three-dimensional geometry.
The is_isosceles command takes as argument a geometric object or three points.
is_isosceles returns 1, 2, 3
or 4 if the object (or triangle formed by the three points)
is an isosceles triangle (the number indicates which vertex is on two
equal sides) or a value of 4 means the triangle is equilateral.
The command returns 0 if the object is not an isosceles
triangle.
Input:
Output:
Input:
then:
Output:
Input:
then:
Output:
Note that T[0] is a triangle since T is a list made
of a triangle and the vertex C. Entering affix(C)
returns sqrt(2)/2 + i*sqrt(2)/2
Input:
Output:
Input:
Output: