Sin is a sine function, and the value of the opposite side of the hypotenuse of a right triangle is the sine value of the angle.

Cos is a cosine function, ———————————————————————————————————————————————————————————————————.

Tg is a tangent function, ———————————————————

Ctg is a cotangent function, ——————————————————————————————————————————————————————————————————————————————————————————————————————————————————————.

Sgn is symbolic, such as SGN (-9) =- 1, SGN (9) =+ 1.

Log is a logarithmic function, that is, the reciprocal of an exponential function. Lg refers to a logarithmic function with base ten, and ln is a logarithmic function with base e, such as lg 100=2, LNE 3 = 3, and so on.

Tg is tan.

I completely forgot. _, you really should check it online.