Discover MakerZone

MATLAB and Simulink resources for Arduino, LEGO, and Raspberry Pi

Learn more

Discover what MATLAB® can do for your career.

Opportunities for recent engineering grads.

Apply Today

Inserting and equation and plotting it

Asked by abdo on 25 Nov 2012

i'm trying to insert an equation and plot it, but i couldn't because i keep getting errors like : matrix dimensions must agree, or inner matrix dimensions must agree.

http://www4.0zz0.com/2012/11/25/10/272913238.png

this is the equation. M has a value of 1 to 5 with an increment of 0.5. Q has a value of 0 to 1 with an increment of 0.1.

the plot is something like this.

http://www4.0zz0.com/2012/11/25/10/700692428.png

thank you in advance, i would appreciate your help

0 Comments

abdo

Products

No products are associated with this question.

2 Answers

Answer by moulay on 25 Nov 2012

Hi!

that is true. length(M)=9 and length (Q)=11. you should take the same length of both vectors. for example Q=0:0.1:0.8!

1 Comment

abdo on 25 Nov 2012

thanx for your reply ok i fixed that issue,i tried to split the equation into parts so it would be easier for me to insert it. lets say (d) represents a part d=q/2*m-arccossqrt(1-(q/m)^2); and it gets me this error 1. error using * the inner matrix dimensions must agree thanx in advance

moulay
Answer by bym on 25 Nov 2012

use the dot notation to specify element-by-element multiplication/division/exponentiation as in:

d= q./(2*m)-acos(sqrt(1-(q./m).^2))

2 Comments

abdo on 25 Nov 2012

thank you, now i have another error for the next part

e=q./m(1-sqrt(1-(q./m).^2));

Subscript indices must either be real positive integers or logicals.

bym on 27 Nov 2012

yes, you are missing a multiplication. I think what you want is

e = (m./q).*(1-sqrt(1-(q./m).^2))
bym

Contact us