[julia-users] Strange results in using symbolic calculation

[Thanh Nguyen]

I am using Julia in my work. Please explain why the following result is so 
strange and how to treat this situation:

using SymPy
x=Sym("x")
f1(x)=x^2
f2(x)=diff(f1(x), x)

subs(f2(x), x, 1)    ==>  2
subs(f2(x), x, 1)<3     ==> false

Thank you.

Thanh Nguyen