Cross ProductIn this example, we are going to write a function to find the cross product of two given vectors u and v. If u = [u1 u2 u3] and v = [v1 v2 v3], we know that the cross product w is defined as w = [(u2v3 – u3v2) (u3v1 - u1v3) (u1v2 - u2v1)]. We can check the function by taking cross products of unit vectors i = [1 0 0], j = [0 1 0], and k = [0 0 1] First, we create the function in an m-file as follows: function w = crossprod(u,v) % We're assuming that both u and v are 3D vectors. % Naturally, w = [w(1) w(2) w(3)] w(1) = u(2)*v(3) - u(3)*v(2); w(2) = u(3)*v(1) - u(1)*v(3); w(3) = u(1)*v(2) - u(2)*v(1); Then, we can call the function from any script, as follows in this example: % Clear screen, clear previous variables and closes all figures clc; close all; clear % Supress empty lines in the output format compact % Define unit vectors i = [1 0 0]; j = [0 1 0]; k = [0 0 1]; % Call the previously created function w1 = crossprod(i,j) w2 = crossprod(i,k) disp('*** compare with results by Matlab ***') w3 = cross(i,j) w4 = cross(i,k) And Matlab displays: w1 = 0 0 1 w2 = 0 -1 0 *** compare with results by Matlab *** w3 = 0 0 1 w4 = 0 -1 0 >> From 'Cross Product' to home From 'Cross Product' to 'Matlab Examples'
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