It is based on the fact that if two arcs have the same sine, then they are congruent or supplemental. So we can write that: sin x = sen a The solution set of this equation will therefore be: Thus we can write that: cos x = cos a x = a + The solution set of this equation will therefore be: Next: Resolution of the 3rd fundamental equation

Spherical zone It is the sphere part generated as follows: The spherical zone area is given by: Spherical cap It is the sphere part generated as follows: The spherical cap area is given by: Spherical spindle The spherical spindle is a part of the spherical surface obtained by rotating a semicircle of an angle about its axis: The area of the spherical spindle can be obtained by a simple three-rule: Spherical Wedge Part of the sphere that is obtained by rotating a semicircle around its axis. axis of an angle: Wedge volume can be obtained by a simple three-rule: Next content: Logarithms