Trig is a shortcut for "Trigonometry"
Trigonometry is a branch of mathematics which mostly deals with triangles. You need trigonometry for any further studies in mathematics (E.g. calculus)
I assume you are referring to basic trigonometry, so, the basic trigonometry deals with right angle triangles as well as general triangles(Triangles not right), but let's start with right angle triangle
We have 3 main functions called trigonometric functions
First: In a right angle triangle, we already know that the side opposite (I.e. in front of the 90-degree angle) is called the hypotenuse. Now pick any other angle from this triangle let's say the upper one (Above the 90-degree angle) we don't know its value (assume) so let's label it \(\theta \) (theta, greek letter usually used for unknown angles). Now the side in front of this angle is called "Opposite side" of this angle, the side next to it (Other than the hypotenuse of course) is called adjacent, with that known and we know the length of the 3 or 2 sides, we can use the following functions to find the value of this angle:
\(sin(\theta) =\frac{opposite}{hypotenuse}\)
\(cos(\theta )=\frac{adjacent}{hypotenuse}\)
\(tan(\theta )=\frac{opposite}{adjacent}\)
Where \(\theta \) is the angle you are trying to find the value of or that you already have.
These laws apply only in right-angle triangles.
