关于 sym 的问题，很简单的！请进！

Viali

问你一个问题，对于下面的程序
fn='2*exp(-x)*sin(x)';
xmin=fmin(fn,0,5)
是可以得到结果的，但是为什么将第一行改成  f=sym('2*exp(-x)*sin(x)');之后就不可以了，为何？

dcyu

X = FMIN('F',x1,x2) attempts to return a value of x which is a local
   minimizer of F(x) in the interval x1 < x < x2.  

'2*exp(-x)*sin(x)' is a string containing the name of the objective function to be minimized.

dcyu

But sym('2*exp(-x)*sin(x)') is only a symbol, not a string.