Q=quad('fx',0,.8)

>> x=[0 .12 .22 .32 .36 .4 .44 .54 .64 .7 .8];>> y=fx(x)

>> integral=trapz(x,y)

>> diff(x)

>> d=diff(y)./diff(x)

>> a=[ 1 1/2 1/3 ; 1 2/3 2/4 ; 1 3/4 3/5 ]

>> b=[1+1/2+1/3;1+2/3+2/4;1+3/4+3/5]

>> cond(a)

>> X=a\b

>> X=inv(a)*b

>> tspan = [0,20];>> y0=[2,1];>> [t,y]=ode23('predprey',tspan,y0);>> plot(t,y)

>> plot(y(:,1),y(:,2))

>> tspan = [0,20];>> y0=[1,1]; >> [t,y]=ode45('vanderpol',tspan,y0);>> plot(t,y(:,1))

function yp = vanderpol(t,y)yp=[y(2);1000*(1-y(1)^2)*y(2)-y(1)];

>> tspan=[0,3000];>> y0=[1,1];>> [t,y]=ode23s('vanderpol',tspan,y0);>> plot(t,y(:,1))

>> clear, clf, hold off>> x1 = 0:0.1:2;>> y1 = -2:0.1:2;>> [x,y] = meshgrid(x1,y1);>> f1 = f_f1(x,y);

>> clear, clf, hold off>> x1 = 0:0.1:2;>> y1 = -2:0.1:2;>> [x,y] = meshgrid(x1,y1);>> f1 = f_f1(x,y);>> f2 = f_f2(x,y);>> contour(x1,y1,f1,[0.00, 0.00])>> hold on>> contour(x1,y1,f2,[0.00, 0.00])>> xlabel (x) ; ylabel (y)