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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
Sine= \frac{Opposite}{Adjacent}  \\ Cosine= \frac{Adjacent}{Hypotenuse}  \\ Tangent= \frac{Opposite}{Adjacent}

Hypotenuse is the longest side, the opposite is the side opposite the angle and adjacent is the remaining side
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