25. Similar formulæ for Cos A, Tan A, Sec A....
26. The Sine, Cosine, Tangent, and Secant of an angle expressed in terms
of the Complement and the Supplement..........
27-30. Formulæ connecting Goniometrical functions together; and Examples
of their application
31. If A be less than 45o, Sin A is less than Cos A............