Question

The angle between two vectors u₁=x₁i+y₁j+z₁k and u₂=x₂i+y₂j+z₂k can be determined by cos($\Theta$)=(x₁*x₂+y₁*y₂+z₁*z₂)/(|u₁|*|u₂|), were |u₁|=sqrt(x₁^2+y₁^2+z₁^1). Given the vectors u₁=3.2i-6.8j+9k and u₂=-4i+2j+7k, determine the angle between them (in degrees) by writing one MATLAB command that uses element by element multiplication and the MATLAB built in functions acosd, sum, and sqrt.

This is what I tried but i don't think it's correct because it should be one value and I got a vector

u1=[3.2 -6.8 9] u2=[-4 2 7] theta=acosd(sum(u1.*u2)./sqrt(u1).*sqrt(u2)).

Answer 1

clc
clear all

u1 = [ 3.2, -6.8, 9 ];
u2 = [ -4, 2, 7 ];

theta = acosd(sum(u1.*u2)/sqrt((sum(u1.^2)*sum(u2.^2))));

fprintf('\ntheata = %0.4f degree\n',theta);