Question

Please solve it with matlab

os Time 2 4 6 7 Voltage 1.1 1.9 3.3 3.4 3.1 3.3 7.1 Fit a straight line through the data points, and then plot this line along with the sample voltages According to your straight line, determine at what time the voltage would be 5

Answer 1

% Matlab script to fit a straight line through a given set of points and
% plot the points and the line and find the voltage for time=5 from that
% plot
% define the variables to hold the time and voltage data
t = [1,2,3,4,5,6,7];
v = [1.1,1.9,3.3,3.4,3.1,3.3,7.1];
% finds the coefficients of a polynomial P(t) of
% degree 1 that fits the data Y best in a least-squares sense.
p = polyfit(t,v,1); % returns the coefficients for a polynomial,p , of degree 1 that is a best fit for the data in v
% returns the value of a polynomial P evaluated at t.
f = polyval(p,t);
% returns the value of the polynomial evaluated at t=5
f_5 = polyval(p,5);
fprintf(' Value of polynomial at t=5 : %f\n',f_5);
plot(t,v,'o',t,f,'-');
xlabel('Time');
ylabel('Voltage');
title('Plot of Voltage vs Time');
grid on;

%end of script

Output:

value of polynomial at t=5 : 4.050000 Figure 1 Plot of Voltage vs Time 6 5 7 4 3 2 4 Time 2 7