You may enter predefined variables ($v1 to $vn), defined results (e.g. $r1), braces for expressions, mathematical operators  + (addition), - (subtraction), * (multiplication), / (division), ^ (nth power), the constants ‘pi’ for pi and ‘e’ for euler's constant, as well as the functions ‘sin’, ‘sinh’, ‘arcsin’, ‘asin’, ‘arcsinh’, ‘asinh’, ‘cos’, ‘cosh’, ‘arccos’, ‘acos’, ‘arccosh’, ‘acosh’, ‘tan’, ‘tanh’, ‘arctan’, ‘atan’, ‘arctanh’, ‘atanh’, ‘sqrt’, ‘abs’, ‘ln’ and ‘log’.