Question 425985
There's also the option of teaching yourself; I had to teach myself algebra. Or hire one of our tutors.


Anyway, the trigonometric functions can be defined using a right triangle, but this is not the universal definition since it is only defined on angles between 0 and {{{pi/2}}}. Here is the right triangle definition:


{{{drawing(200,200,0,10,0,10,

triangle(2,2,8,2,8,7),
locate(2.5,2.5,theta),
locate(5,1.8,a),
locate(8.2,4.5,b),
locate(4.8,5.2,c)

)
}}}


Here, the Greek letter {{{theta}}} represents an angle. We define the trigonometric functions as follows:

{{{sin(theta) = b/c}}}, {{{cos(theta) = a/c}}}, {{{tan(theta) = sin(theta)/cos(theta) = b/a}}}

We also have trigonometric functions cosecant, secant, and cotangent. They are defined like this:

{{{csc(theta) = 1/sin(theta) = c/b}}}, {{{sec(theta) = 1/cos(theta) = c/a}}}, {{{cot(theta) = 1/tan(theta) = a/b}}}.