Solving for Symbolic Standard Deviation

Hi.

I don't know Matlab that well, but I've been trying to find a command
to solve a function to find the equation for standard deviation.

I know there is the std equation, but I need to be able to specify
the standard deviations of each of the parameters (there are 15 of
them).

I'm solving for stresses in an object and my dimensional and force
tolerances are known.

Is there a way to solve a symbolic equation and have it spit out to
me a standard deviation equation?