Making determinant zero

Hello,

I am stuck with a n by n matrix (4 by 4 actually) which has variables in it. I need to find values of that variable for which determinant of the matrix becomes zero, i.e. the matrix becomes singular. I need a numerical analysis in MATLAB. Can anyone help?

Answer 1

[Sean de Wolski]

How about the quick and shoddy numerical way?

x = magic(4);
fzero(@(y)det(x.*y),pi)

Answer 2

[Walter Roberson]

A symbolic analysis would be easier. For example,

syms y
x = sym(magic(4));
x(1,3) = 7+y^2;
x(4,2) = cos(y);
solve(det(x),y)