%3.1
T =[40 50 60]';
P = [55.3 92.5 149.4]';
A = [ones(size(T)) T T.^2];
x = A\P;
Tplot= 40:60;
Pcurve = x(1)+x(2)*Tplot+x(3)*Tplot.^2;
plot(Tplot, Pcurve); hold on;
plot(T,P, 'r*'); hold off;
