MATLAB: How to create a new matrix with some known rows

arrayfindmatrix

Hello everyone,

Suppose matrix a is like:

a = [2;3;6;2];
b = [1 3 6;2 3 7;2 2 1;3 1 9;3 2 8;4 1 5];

Then, I want matrix c to be like:

c = [2 3 7;2 2 1;4 1 5;2 3 7]

Matrix c is included all row numbers from matrix b which is in matrix a.

c = b(a,:)

[a(:,2:3),b(:),c]

With the values you provided, ‘eqn2’ equates to 0, so there is nothing to solve for.

That aside, you are solving one equation for two unknowns, so you will likely not get the result you intend:

syms a b c
% a = -500;
b = 433;
% c = -866;
eqn2 = (-0.5*a-0.866*c) == 1000;
S = solve(eqn2,[a,c]);
a = S.a
c = S.c

producing:

a =
-2000
 
c =
0