Trigonometric functions
There are three main trigonometric functions, and they are all based on right triangles. Let's use the right triangle, as follows:
Figure 12.6 – A right triangle [6]
We will call the angle at A on the triangle θ. The angle at C is 90 degrees or a right angle. The three trig functions are called sine, cosine, and tangent. Here are their definitions along with their abbreviations:
There are three other trig functions, which are the inverse of the main three and have the special names of cosecant, secant, and cotangent. Here are their definitions:
Given this, common values for these functions can be seen in the following table:
Figure 12.7 – The common values for sin, cos, and tan
As angles get bigger, they move from the first quadrant into the three other quadrants and become positive or negative, based on the values of x and y in those...
