# Inserting and equation and plotting it

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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.
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.

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!
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

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))
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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))