Think of the trigonometric functions as percentage , did you ever wonder why sine and cosine go from 1 to 1 ? For example in this picture is the length of your '' wall '' compared to your '' ceiling '' or hypotenuse , think about it , if your angle is 0 your ceiling lays flat , and you have no '' wall '', thus sin 00 , but what about your '' floor '' or cosine ? When the angle is 0 your ceiling collapses to the floor , thus the length of your '' floor '' is the whole ceiling , or in math cos 01 . This explanation was taken from this site that I highly recommend for the intuition behind mathtrigonometry <| sep |> Great effort but this isnt the 90 s . You could have audio attached , and video if you really wanted , with a free flashcard program , not to mention spaced repetition systems .