求函数f(x)=cosx+sinx,x属于[0,π]的值域

>> fun1=inline('sin(x)+cos(x)','x');
fun2=inline('-sin(x)-cos(x)','x');
min_x=fminbnd(fun1,0,pi);
max_x=fminbnd(fun2,0,pi);
fun1([min_x,max_x])

ans =

-0.999954051951746 1.414213562361815

即值域是[-1,1.414213562361815]

y=sinx+cosx的值域[-根号2，根号2]