Sin is the ratio of the opposite side to the hypotenuse, cos is the ratio of the adjacent side to the hypotenuse, and tan is the ratio of the opposite side to the adjacent side. They are often written as sin(x), cos(x), and tan(x), where x is an angle in radians or degrees. Created by Sal Khan. Sine, Cosine and Tangent are all based on a Right-Angled Triangle. They are very similar functions so we will look at the Sine Function and then Inverse Sine to learn what it is all about. Sine Function. The Sine of angle θ is: length of the side Opposite. divided by the length of the Hypotenuse. Or more simply: sin ( θ) = Opposite / Hypotenuse Generalized trigonometry. Reference. Identities. Exact constants. Tables. Unit circle. Laws and theorems. Sines. Cosines. Tangents. Cotangents. Pythagorean theorem. Calculus. Trigonometric substitution. Integrals ( inverse functions) Derivatives. v. t. e. Trigonometry. Share. Watch on. The Graphs of Sin, Cos and Tan - (HIGHER TIER) The following graphs show the value of sinø, cosø and tanø against ø (ø represents an angle). From the sin graph we can see that sinø = 0 when ø = 0 degrees, 180 degrees and 360 degrees. The calculation is simply one side of a right angled triangle divided by another side we just have to know which sides, and that is where "sohcahtoa" helps. For a triangle with an angle θ , the functions are calculated this way: Example: what are the sine, cosine and tangent of 30° ? qoCg.

sin cos tan laws