Example from class on Monday, Jan. 27

Contents

(a)

For the two points P=(1,1,0) and Q=(0,0,1) find the distance between the two points.

P = [1,1,0]; Q = [0,0,1];
a = Q - P                     % vector from P to Q
distance = norm(a)

a =
    -1    -1     1
distance =
    1.7321

(b)

Find the midpoint R between the points P and Q.

Find the midpoint S between the points P and R. Find the midpoint T between the points R and Q.

Plot the line connecting the points P and Q. Mark the points P,Q,R,S,T.

R = P + .5*a                  % midpoint of P and Q, same as (P+Q)/2
S = P + .25*a
T = P + .75*a

plotpts([P;Q],'o-')           % plot line from P to Q, mark endpoints with circles
hold on                       % add the following stuff to this plot
plotpts([R;S;T],'o')          % plot points R,S,T, mark with circles
texts(P,'P'); texts(Q,'Q');   % label points
texts(R,'R'); texts(S,'S');  texts(T,'T');
hold off                      % we're done with this plot
nice3d                        % make plot look nice
                              % you can rotate plot with mouse in Matlab window
view(10,20)                   % pick nice angle to look at plot

R =
    0.5000    0.5000    0.5000
S =
    0.7500    0.7500    0.2500
T =
    0.2500    0.2500    0.7500

Published with MATLAB® R2013b