function v = skydiver_func6
% Function to calculate skydiver falling speed
% for specified parameter values and time vector
% using the analytic solution.
%
% Inputs:  mass m (kg)
%          gravity g (m/s^2)
%          drag coefficient c (kg/m)
%          time vector (s)
%
% Outputs: falling speed vector v (m/s)

% Read inputs from a data file called data.txt
data = load('data.txt');
nrows = size(data,1);

m = data(1,1)
g = data(2,1)
c = data(3,1)
t = data(4:nrows,1)

v = sqrt(m*g/c)*tanh(sqrt(g*c/m)*t);

% Save time and calculated speed vectors to a text file
save speeds1.txt t v -ascii -double -tabs % data in one long column

outputs = [t v];
save speeds2.txt outputs -ascii -double -tabs

% Save time and calculated speed vectors to a text file
% as two formatted columns
fid = fopen('speeds3.txt','w');
fprintf(fid,'  Time      Speed\n');
fprintf(fid,'  %3.1f      %5.2f\n', t, v);
fclose(fid);