We see sine and cosine in a scientific calculator all the time. These are used in trigonometry. They are used in right triangles, triangles with a measure of 90° on a side.
The usual thing said for remembering the formulas is SOHCAHTOA
which means
[tex]Sine= \frac{Opposite}{Adjacent} \\ Cosine= \frac{Adjacent}{Hypotenuse} \\ Tangent= \frac{Opposite}{Adjacent} [/tex]
Hypotenuse is the longest side, the opposite is the side opposite the angle and adjacent is the remaining side
