how to plot two graphs combined

I need to plot P=0.5+thetax on 0<x<0.33 and then P=theta(x-1) on 0.33<x<1. Do i use a for loop to do this? And if so how? Here is my code so far

x=linspace(0,1,50);
g=10;
A=0.33
M=0.125
s=(A-0.5)*M.*g-(A^2)/4;
theta=s./(2*M.*(A-0.5)^2+2*M+(A^2-A+1/3)/2);
P=(1/2)+theta*(x-1);
plot(x,P)
axis([0,1,-2,2])

Answer 1

[Ben11]

Maybe something like this:

x=linspace(0,1,50)

g=10;
A=0.33
M=0.125
s=(A-0.5)*M.*g-(A^2)/4;
theta=s./(2*M.*(A-0.5)^2+2*M+(A^2-A+1/3)/2);
P=(1/2)+theta*(x-1);

xS = x< 0.33 % define x < 0.33
xL = x>0.33 % define x > 0.33

figure

plot(x(xS),0.5+theta*x(xS))

hold on

plot(x(xL),theta*(x(xL)-1))

hold off

axis([0,1,-2,2])

[Josie]

Thanks! Is there any way to get a vertical line joining the two?

[Ben11]

Yes there is! I modified the code a bit so it's easier to play around with it:

x=linspace(0,1,50);

g=10;
A=0.33;
M=0.125;

s=(A-0.5)*M.*g-(A^2)/4;
theta=s./(2*M.*(A-0.5)^2+2*M+(A^2-A+1/3)/2);

P=(1/2)+theta*(x-1);

xS = x(x < 0.33);
xL = x(x > 0.33);

StartLine = 0.5+theta*(xS(end)); % Retrieve x values for starting/ending points of the line
EndLine = theta*(xL(1)-1);

figure

plot(xS,0.5+theta*xS)

hold on

plot(xL,theta*(xL-1))

line([xS(end) xL(1)],[StartLine EndLine],'Color','r','LineWidth',2)

hold off

axis([0,1,-2,2])

The line is thicker than the plots and red as well; you can customize this as you wish :)

[Josie]

Great! Thank you

[Ben11]

My pleasure!