help me with my maths

I believe you meant $\sin(x), \cos(x)\text{, and }\tan(x)$.

We have a mnemonic for that, namely "SOHCAHTOA".

In the following diagram:

AB is opposite to x, so we call it "opposite side"

AC is adjacent to x, so we call it "adjacent side".

BC is the "hypotenuse".

The mnemonic "SOHCAHTOA" helps us remember the following relations:

$\color{red}\text{s}\color{black}\text{in}\;x = \dfrac{\color{red}\text{o}\color{black}\text{pposite side}}{\color{red}\text{h}\color{black}\text{ypotenuse}}$

$\color{red}\text{c}\color{black}\text{os}\;x = \dfrac{\color{red}\text{a}\color{black}\text{djacent side}}{\color{red}\text{h}\color{black}\text{ypotenuse}}$

$\color{red}\text{t}\color{black}\text{an}\;x = \dfrac{\color{red}\text{o}\color{black}\text{pposite side}}{\color{red}\text{a}\color{black}\text{djacent side}}$