# Revision history [back]

I think you want v = function('v') for the first line; the first argument is the name of the function.

Here's the full code:

v = function('v')
u(x) = (v(x) + v(-x))/2
delta = 10^(-90)
u(delta).substitute_function(v, gamma)


I think you want v = function('v') for the first line; the first argument is the name of the function.

Here's the full code:

v = function('v')
u(x) = (v(x) + v(-x))/2
delta = 10^(-90)
u(delta).substitute_function(v, gamma)


I'm puzzled as to why it doesn't work if v is defined as v = function('v', x). Anyone know?