input:
    sqrt(2 - sin(3*A/B)^2.5) + 0.5*(C*~(D) + 3.11 +B)
    a
    b   /*there are values for a,b,c,d */
    c
    d
    input :
    sqrt(2 - asin(3*A/B)^2.5) +cos(0.5*(C*~(D)) + 3.11 +B)
    a
    b   /*there are values for a,b,c,d */
    c
    d
    input:
    sqrt(2 - sin(3*A/B)^2.5)/(0.5*(C*~(D)) + sin(3.11) +ln(B))
     /*max lenght of formula is 250 characters*/
    a
    b   /*there are values for a,b,c,d */
    c   /*each variable with set of floating numbers*/
    d

 As you can see infix formula in the input depends on user.
 My program will take a formula and n-tuples value.
 Then it calculate the results for each value of a,b,c and d.
 If you wonder I am saying ;outcome of program is graph.
 I dont know way how to store the formula  so that I can do my job with easy.
 can you show me?
 a,b,c,d is letters
 cos,sin,sqrt,ln is function