why？
 

F=@(t)((R-y1.*cos(t)-x1.*sin(t))./((sqrt((x1-R.*cos(t)).^2+(y1-R.*sin(t)).^2+(z1-z0).^2)).^3)
??? F=@(t)((R-y1.*cos(t)-x1.*sin(t))./((sqrt((x1-R.*cos(t)).^2+(y1-R.*sin(t)).^2+(z1-z0).^2)).^3)
|
Error: Incomplete or misformed expression or statement.

who can tell me why this is wrong？ thanks！