Can someone tell my what cos, sin and tan actually measure?
In: Mathematics
It doesn’t “measure”.
It relates the angle(s) in a triangle to the ratio of distances of it’s sides.
People realized that if you measured the sides of a right triangle and divided the side lengths by each other, you always got the same numbers for triangles that were the same shape, no matter how big or small they were. They gave names to the three ways you could divide three side lengths and wrote them down in tables, one row for every possible angle. Then they taught computers how to remember them.
* sin: how far up you go when you go one unit of distance along a slope of some angle (i.e., the vertical distance)
* cos: how far over you go when you go one unit of distance along a slope of some angle (i.e., the horizontal distance)
* tan: the slope expressed as rise over run
Look at [this gif](https://upload.wikimedia.org/wikipedia/commons/3/3b/Circle_cos_sin.gif)
As something goes around in a circle, *cosine* measures the way the x-component (horizontal location) of the thing changes as it moves around the circle, and *sine* measures the way the y-component (vertical location) of the thing changes as it moves around the circle.
Sine and Cosine measure the two components of circular motion.
*Tangent* is just *sine*/*cosine*
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