An expression is some combination of constants, variables, functions, and operators. For example:
A*COSD(X/10)+3.5*SIND(X/12)+C*EXP(-X)
Input is limited to 255
characters, so to have expressions
that are longer, use character variables to store its pieces. For example:
F1 = '2.5*COS(X/10)+3.5*SIN(X/12)+63.7*EXP(X/45)'
F2 = '1.234567*MOD(X,100)+SIN(X/1000)*EXP(X/200)'
F3 = '3.56789*X^2-2.34567*X+23.456'
Y = F1+F2+F3