@acer 

Thank you. I have sorted this out already.

@mmcdara 

Please, just ignore my last comment. I understand it now.

@mmcdara 

Thank you for this. I wanted something like after I must have collected the coefficient for both 

(alpha[1]*cos(theta(x, y, t))^2*sin(theta(x, y, t))^2+(alpha[2]+alpha[3]+alpha[6]-alpha[5])*((1/4)*cos(theta(x, y, t))^2-(1/4)*sin(theta(x, y, t))^2)+(1/2)*alpha[4]+(alpha[5]+alpha[6])*((1/4)*cos(theta(x, y, t))^2+(1/4)*sin(theta(x, y, t))^2)+(alpha[3]-alpha[2])*((1/4)*cos(theta(x, y, t))^2+(1/4)*sin(theta(x, y, t))^2))*dudy^2   + (alpha[1]*cos(theta(x, y, t))^2*sin(theta(x, y, t))^2+(alpha[2]+alpha[3]+alpha[6]-alpha[5])*(-(1/4)*cos(theta(x, y, t))^2+(1/4)*sin(theta(x, y, t))^2)+(1/2)*alpha[4]+(alpha[5]+alpha[6])*((1/4)*cos(theta(x, y, t))^2+(1/4)*sin(theta(x, y, t))^2)+(alpha[3]-alpha[2])*((1/4)*cos(theta(x, y, t))^2+(1/4)*sin(theta(x, y, t))^2))**dvdx^2 

But it doesn't collect the coefficients of *dvdx^2.

@mmcdara 

Thank you for this. I don't want them separate. I want to collect the coefficient of dudy^2 and dvdx^2 in the bigger equation. I have been able to collect them separately but this not what I want. 

Please ignore this. 

I tried "add" instead of sum and it worked.

@Carl Love

Thank you 

@Christian Wolinski 

Thank you, Christian

@dharr 

Thank you so much

Hi Tomleslie here is the link to my code: NNMMM.mw

@dharr 

Thank you 

@tomleslie 

Thank you for the explanation

@tomleslie 

I'm kind of confused. Please in mydata, which column corresponds to xi =0 and xi =0.1. I want to differentiate them for plotting purposes.

@tomleslie

 Thank you very much. I really appreciate your help

@tomleslie 

Maybe I attached the wrong file. In the file: Case1_Revised_080922.mw the line has: 

ExcelTools:-Export(op([1, 1], plots:-display( convert( ans1[12..14,3], list))));

You may be wondering why am I doing this. While I wanted to export my data from maple to Matlab and compare it with my result in Matlab. I tried to export it as a Matlab script but couldn't work. So I had to use ExcelTools. So, I exported only my plots which are okay for only one value of xi. But for several values of xi, it couldn't work. If there are other alternatives, I need your suggestion.

@Carl Love

Thank you