More Basic Trig

Every angle has a sin or cosine or tan (well, not quite every angle, in the case of tan). You can use this value to find the angle, doing it easily on a calculator.

You just press sin^-1 .456 or whatever it is, and that gives you the angle (if you have the calc. set to degrees that is).

The Really Basic Basics of Trig

Trig is basically to do with triangles and circles. It works from the properties of angles relative to the sides of triangles and how these can be seen in circles (unit circles - with a radius of 1). It's used to tell you the size of angles and sides using other information you already know about the triangle.

The trig identities, I reckon, are probably best defined as ratios.

All fractions are ratios, as well as being processes.

For a right angled triangle (where we tend to begin with these)

SohCahToa

Sin =opposite/hypotenuse

Cos = adjacent/hypotenuse

Tan = opposite/adjacent


For each angle, there will be a different value for each one of these. So sin 42 will be the same whatever triangle you have. It regulates what the sizes of the opposite and hypotenuse will be only in terms of the ratio between them.

Sin and Cos (not sure about Tan) will always give a value between 1 and -1 inclusive.