Using VBA Excel functions in analytical geometry

The article contains the software codes of two VBA Excel custom functions. The first function finds either the coordinates of the point of intersection of two straight planes, or the tangent of the angle between them, or the slope of the straight line, in which a ray of light, while moving along the first straight line, moves after the reflection from the second line. The second function finds either the distance between intersecting lines, or the coordinates of the point, through which passes the common perpendicular of the intersecting lines, or the guiding vector of their common perpendicular, or the parametric equations of their common perpendicular, or the distance from a given point of the first straight line to the second straight line. All calculations are performed online and do not require Excel worksheet data. The application of the developed custom functions is demonstrated through specific tasks.