Question

Matlab fzero()函数使用问题，新手求教

>> k=0.6;
>> r=fzero('cos(x)-k',[1 2]);
Error using fzero (line 233)
FZERO cannot continue because user supplied expression
==> cos(x)-k failed with the error below.
Error in inline expression ==> cos(x)-k
Undefined function or variable 'k'.
要怎么才能把k=0.6 带进cos(x)-k里面啊 subs还有double都试过了= =

Answer 1

可这样：
k=0.6;
f=@(x)cos(x)-k;
r=fzero(f,[0,pi/2])
结果是：
r =
0.9273

Answer 2

k=0.6;
equ = cos(x)-k;
r=fzero(eq,[1 2]);

追问

k=0.6;
equ = cos(x)-k;
r=fzero(equ,[1 2]);
Error using fzero (line 169)
If FUN is a MATLAB object, it must have an feval method.
还是不行= =

追答

syms x
k=0.6;
equ = cos(x)-k;
r=fzero(eq,[1 2]);
加上第一句试试