MATLAB: I want to find vector of determinants

determinantvector

a= 1 x 4 vector

b= 1 x 4 vector

c= 1 x 4 vector

d= 1 x 4 vector

-my code-

 detvector=det([a b c d]);

-I want to get detvector=[det([a(1) b(1); c(1) d(1)]),det([a(2) b(2); c(2) d(2)]),det([a(3) b(3) ;c(3) d(3)]),det([a(4) b(4); c(4) d(4)])]. But my code doesn't works. How can I solve it?

Best Answer

Your code is correct, you can use arrayfun function

out=arrayfun(@(x) det([a(x) b(x);c(x) d(x)]),1:numel(a))

Related Solutions

MATLAB: I want to get vector of det

If you express the matrix properly as a 4 x 4 matrix,

 det([a;b;c;d]),

matlab will give you its determinant. Your expression

 [a b c d]

is that of a 1 x 16 row vector and it is meaningless to speak of its "determinant".

However, you don't need matlab to find the determinant you apparently have in mind. Of the twenty-four products that comprise this determinant, only one is non-zero and that will be the product of the four 1's, giving you a resultant determinant value of 1.

MATLAB: How to get the positive root of the cubic ax^3+3b*x^2+3cx+d=0

You can try

b = .1:.1:2;
a = 1;
c = b+2;
d = -3;
posR = zeros(1,length(b));
for i = 1:length(b)
    r = roots([a,3*b(i),3*c(i),d]);
    posR(i) = r(r>0); % only one real root for the values you specified
    posR(i) = posR(i)/(posR(i)+1);
end

Best Answer

Related Solutions

MATLAB: I want to get vector of det

MATLAB: How to get the positive root of the cubic a*x^3+3*b*x^2+3*c*x+d=0

Related Question

MATLAB: How to get the positive root of the cubic ax^3+3b*x^2+3cx+d=0