Change exp from number to e

Im doing a little work on matlab and Im trying to type some expressions that include the number e. However, when I do this, instead of putting the e, it puts a fraction that aprroximates the value. Does anyone know how to change this?

syms c1 c2 y(x) f(x)
y(x) = (exp(2)/(exp(2)+1))*exp(-x)+(1/(exp(2)+1))*exp(x)

y(x) = 

ans = y(0)

ans = 

And as you can see, this causes it to not give an exact answer, y(0) should be 1, when it instead gives a really close approximation

Answer 1

[Rik]

Your own suggestion actually works (although it requires a call to simplify):

syms c1 c2 y(x) f(x) e
y(x) = (e^2/(e^2+1))*e^(-x)+(1/(e^2+1))*e^x

y(x) = 

y=simplify(y)

y(x) = 

y(0)

ans = 

1

You can also use subs to substitute e with exp(1).

Answer 2

[Paul]

Use sym arguments to exp, otherwise it reverts to the base Matlab numerical function.

syms c1 c2 y(x) f(x)
y(x) = (exp(sym(2))/(exp(sym(2))+1))*exp(-x)+(1/(exp(sym(2))+1))*exp(x)

y(x) = 

Evaluate at some values

simplify(y([0 1 2]))

ans = 

vpa(ans)  % etc.

ans =