The form you should use may be given to you in a question, but if not, any one will do. If in doubt, \(k\cos (x - \alpha )\) usually works. These worked examples show the processes you'll need to go ...

The three sides of a right-angled triangle have special names. The hypotenuse (\(h\)) is the longest side. It is opposite the right angle. The opposite side (\(o\)) is opposite the angle in question ( ...