Properties of exponentials - symbolic algebra

Hello all,

I am experiencing problems with the properties of exponentials, in particular when the exponent is a symbolic variable.

For example, if I set

syms x y

and I want to evaluate

exp(x)*exp(y)

is there a way of having the result the exponential with the sum of exponents

exp(x+y)

instead of the uncomfortable exp(x)*exp(y)?

Notice that it does work for one variable only, i.e. exp(x)*exp(x)=exp(2*x)

Thank you very much!

Answer 1

[Mischa Kim]

Hi Luca, use

syms x y
z = simplify(exp(x)*exp(y))

z = 

[Luca Lazzizzera]

Hello, thank you for answering.

It works as long as the variables are just "x" and "y", but it does not always work, in particular if the product of exponentials is a term in a sum with other terms like exp(x)

for example 6*exp(x) + 5*exp(-x)*exp(y) + 4*exp(-2*y)*exp(x)

does not get simplified for some reason (I have to compute partition functions with many summed terms like this, many more than 3).

Up to 2 added terms, it seems to work instead.

Is there any other more powerful/reliable way?

Thank you again