# Zeroes on an equations with a variable of a specific range

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Fuad Alami on 13 Nov 2016
Answered: Yeshwanth Devara on 16 Nov 2016
I'm trying to find zeroes for a specific function but I keep on getting this error message:
"Error using fzero (line 428)
Second argument must be a scalar or vector of length 2.
Error in Problem3b (line 14)
x=fzero(fun,E)"
My current set up looks as such:
m=9.11*10^-31;
hbar=1.055*10^-34;
e=1.602*10^-19;
Vo=(1.42-0.354)*e;
L1=(4*10^-9);
L2=(10*10^-9);
m1=0.067;
m2=0.025;
meff=((2*m1*m*L1)+(m2*m*L2))/(2*L1+L2);
range=linspace(0,Vo,10^6);
E=linspace(0,Vo,200);
k=(sqrt(2.*meff.*E))./hbar;
B=(sqrt(2.*meff.*(Vo-E)))./hbar;
fun=@(E) ((sqrt(2.*E.*(Vo-E)))/(2.*E-Vo))-(tan(k.*L2).*tan(h.*B.*L1));
x=fzero(fun,E)
##### 2 CommentsShowHide 1 older comment
Fuad Alami on 13 Nov 2016
Yeah, I don't really code so I have no idea where to start with what. Got throwen into a 4th year phys-eng class with no prior matlab experience....

Yeshwanth Devara on 16 Nov 2016
As Jan suggested, the second argument expects a real scalar or a 2-element real vector. It appears the second argument in your case is a 1x200 vector. Refer to the documentation for more information on fzero function and its input arguments.