# Exercici 9.12

kill(all)$

f(x):= 0.51 + 0.42*x + 0.35*x^2;

wxplot2d([f(x)], [x,0,1], [y, 0, 1.5], [ylabel, ""] , [legend, "f(x)"] , [style, [lines, 2]] ,
 [gnuplot_preamble, "set size ratio 1; set zeroaxis; set grid"])$

define ( Df(x) , diff(f(x),x) );

'L=L: integrate ( sqrt(1 + (Df(x))^2), x, 0, 1);

%, numer;