Sin, cos, tan
In a nutshell
sin(), cos(), and tan() are the three main trigonometric functions and serve as the basis of trigonometry. Using the labels in a right-angled triangle, one can define these functions and their corresponding ratios.
Labelling a triangle
Label | Meaning |
x | The angle you're focusing on (you will either have to find out the value of x or use it to find the length of a side) |
Hypotenuse | The longest side of the triangle |
Opposite | The side opposite the angle labelled x |
Adjacent | The side next to the labelled angle that isn't the hypotenuse |
The three trigonometric functions
These are the three main functions and their ratios:
Function name | Found on your calculator as | Corresponding ratio | Simplified version |
Sine | sin() | sin(x)=hypotenuseopposite | SOH |
Cosine | cos() | cos(x)=hypotenuseadjacent | CAH |
Tangent | tan() | tan(x)=adjacentopposite | TOA |
Note: It is common and easy to just remember these three ratios as SOHCAHTOA.