Have you ever seen a sin() function or even a cos() function on a calculator and didn't understood what it meant? This article has you covered on the three basic functions in trigonometry.
ISAIAH LOPEZ
There are six basic trigonometric functions. In this article, we will look at three. These three are the sine, cosine and tangent. Let's start with an equation. In a right triangle, the sine, cosine, or tangent will apply to either of the two non-right angles. For example, the sine function is the opposite over the hypotenuse. The opposite means the side of the triangle opposite the angle specified.
As specified earlier, the sine of an angle is equal to the side opposite the angle divided by the hypotenuse. For example, if you have a triangle with sides 1, √3, and 2, with a 30 degree angle. The sine of this angle would be the opposite, which would be 1, over the hypotenuse, which would be two. This means that the sine of a 30 degree angle would be 1/2. Below is a diagram for better visualization.
Now lets go over the cosine function. The cosine of an angle is equal to the adjacent side divided by the hypotenuse. In case you don't know, the adjacent side is the side that is next to the angle. You might be confused because there are actually two sides next to the angle. One of them, however, is the hypotenuse. The hypotenuse is always the longest side and it is always opposite the right angle. Below is a diagram to help visualize the cosine function.
Now that we have the sine and cosine functions out of the way, we will go over the tangent function. Unlike the sine and cosine functions, the tangent function does not divide by the hypotenuse. It is actually equal to the opposite side divided by the adjacent side. Since the tangent function is structured like this instead, it is actually graphed differently and has different behaviors. That's for another lesson, however.
Hopefully you understand these three basic trigonometric functions. In the next lesson, we will learn about the other three. Don't worry, it's even easier to learn them once you understand these three! Before you go, if you are having trouble remembering which functions do what, just remember soh cah toa. "soh" stands for sine-opposite-hypotenuse, because it divides the opposite side over the hypotenuse. "cah" stands for cosine-adjacent-hypotenuse and "toa" stands for tangent-opposite-adjacent.