why do i keep getting index exceeds matirx dimensions?

I just typed in simple codes for plotting a graph and i keep getting the same error why is that?

d=1:1:10
theta=pi/4;
Dc= d/2.*(1-cos(theta));
Q= (2.^(3/2).*Dc.^(5/2).*sqrt(g).*(theta-0.5.*sin(2.*theta)).^(3/2))/(8.*sqrt (sin(theta).*(1-cos(theta).^(5/2))))
subplot (2,1,2);
plot (d,Q)
title('17473981')
xlabel('diameter')
ylabel('flow rate')
grid on

Answer 1

[the cyclist]

What is "g"? If I set g=1, your code works for me.

Might you have accidentally define your own variable named "cos", "sin", or "sqrt", so MATLAB thinks it is indexing a variable?

[parsh]

yeah, i forgot value of g

g=9.8

but i still get the same error, the error is in the labels and title somehow. if i do xbale = something

than it works but i do not get and labels on graph

thanks.

[the cyclist]

What happens if you restart MATLAB and type in those exact lines?

[parsh]

umm... it works. :) thank you so much

[the cyclist]

Glad it worked, but that drastic solution does not necessarily help you understand where you went wrong. My best guess is that maybe you accidentally defined a new variable (maybe "xlabel") and MATLAB was trying to access that instead of the built-in function.

Answer 2

[Rick Rosson]

Please post the exact error message and indicate which line is triggering the error.

[parsh]

the exact error is

"Index exceeds matrix dimensions."

and it comes up when i define the title and lables

[Image Analyst]

Funny - I get "Undefined function or variable 'g'."

[parsh]

yeah i forgot to put in the value of g, my mistake. thanks you