MATLAB: How to find a global minimum

global minimumoptimization

If I try to search the minimum of the function (that now I use as example) y=(1.2^-x)*sin(x), writing the following code, I obtain a local minimum, depending on the starting point choice.
fun=@(x) (1.2^-x)*sin(x)
xmin =
fval =
The value is correct looking at the function graph, but how can I find the global minimum? My function to minimize is more complicated, so it has a lot of local minima points, and it is impossibile to guess what is the best starting point