It is of the form ans=eval(S) where S is a symbolic expression for which at least one of its symbolic variables has just been given a value. The result g is still a symbolic variable or symbolic constant in “Maple”.Įxample 1: Consider a function of the two Cartesian coordinates f(x, y) =Ĭhange to polar coordinates using x = r cos θ, y = r sin θ and then determine the value of f at an arbitrary point on the unit circle r = 1.į=subs(f,) Īn alternative is to use the eval command. Then you can use the general subs command g=subs(f,old,new) which in our cases would be g=subs(f,x,c) or g=subs(f,x,x0). Suppose you have a symbolic expression f which includes the symbol x and you wish to substitute for x another symbol c or a numerical value x0. Variable substitution and expression evaluation: subs, eval
