Polynomials: (like x^3 + 3x^2 - 5x + 2)
Trigonometric functions: sin(x), cos(x/2), tan(2x), csc(3x), sec(x/4), cot(x)
Sign: returns 1 if the sign of the function value is positive, -1 if the sign of the function is negative. For example, try sign(sin(x)).
ceiling: ceil(x) and round: round(x)
The hyperbolic functions and their inverses: sinh(x), cosh(x), tanh(x), arcsinh(x), arccosh(x), arctanh(x)
Inverse trigonometric functions: arcsin(x), arctan(x), arccos(x), arccsc(x), arcsec(x), arccot(x)
square root: sqrt(x)
Straight lines: (like 3x - 2)
random: random(x);
Absolute value: use "abs" like this: abs(x)
logarithm (ln(x) and Exponential (e^x) for natural log. For log base 10 you need to put ln(x)/ln(10). I'm using Change of Base rule.)
You can also use any combinations of the above, like "ln(abs(x))" (without the quotation marks, of course).
Here you can get graph linear functions calculator.