Sollya User's Manual

Name:

substitute replace the occurrences of the free variable in an expression.

Library name:

sollya_obj_t sollya_lib_substitute(sollya_obj_t, sollya_obj_t)

Usage:

substitute(f,g) : (function, function) -> function substitute(f,t) : (function, constant) -> constant

Parameters:

f is a function.
g is a function.
t is a real number.

Description:

substitute(f, g) produces the function (f o g) : x -> f(g(x)).
substitute(f, t) is the constant f(t). Note that the constant is represented by its expression until it has been evaluated (exactly the same way as if you type the expression f replacing instances of the free variable by t).
If f is stored in a variable F, the effect of the commands substitute(F,g) or substitute(F,t) is absolutely equivalent to writing F(g) resp. F(t).

Example 1:

   > f=sin(x);
   > g=cos(x);
   > substitute(f,g);
   sin(cos(x))
   > f(g);
   sin(cos(x))

Example 2:

   > a=1;
   > f=sin(x);
   > substitute(f,a);
   0.84147098480789650665250232163029899962256306079837
   > f(a);
   0.84147098480789650665250232163029899962256306079837