% hints/ideas for 3.9.17 c plot:

F = 2;                      % best to set up variables as in problem
% let's say your D(w) func was D = sqrt(1 + w^2)
D = @(w) sqrt(1 + w.^2);    % Note need .^ symbol (rather than ^) here to take
                            % power of each element of w separately!
w = 0:0.01:5;               % Set up array of w values to compute
R = F./D(w);                % Again, note the ./ since want to divide by each
                            % element of vector D(w) separately
plot(w, R); xlabel('\omega'); ylabel('R');   % nice greek symbol in label
