You are excellent. Thank you again.

Thank you for everthing. Now I don't use mathematica. It was long time ago. In maple all datapoints must be written by hand. I just wondered why maple doesn't get e.g  X=-1,-0.9,-0.8,-0.7..........0.7,08,0.9,1 and also  Y= -60,-50,-40,...........40,50,60 respectively. That's, X=-1 and Y=-60, X=-0.9 and Y=-50,.............X=1 and Y=60,  X=0.9 and Y=50 etc. What I am saying is that maple doesn't get data points automatically (step by step) when you put  X=-1..+1 and  Y=-60..+60 .

Bengu 

Thank you for your cooperation. Data is enough but maple does not work to calculate A and B parameters or I do not know how to do. I am interested in maple how to calculate this or similar functions.I calculated a similar function by using mathematica a few year ago that's it works.

I think Polynomial Interpolation could be a solution. I used this method. But I want to use e.g. all data among -60 and 60 and also -1 and +1. Is that possible?

Thank you. I'll think about it.

Thank you for your comment . But I  have only X= cos(theta)= -1..1 and Y= -60..60 . That is ,how can I put these values to find A and B?