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MATLAB Central > MATLAB Newsreader > fitting curve at polar coordinate 

Subject: fitting curve at polar coordinate From: Mohammad Seraj Date: 27 Feb, 2012 20:58:11 Message: 1 of 18 
I have some empirical data point at xy coordinate from my research and a suggested equation in polar coordinate derived from a modeling. The equation after simplification is like (R=a/(1 + b cos(theta) ), where a and b are constants to be found. I want to evaluate a, b coefficients from my data. 
Subject: fitting curve at polar coordinate From: Michael W. Date: 23 Mar, 2012 14:56:12 Message: 2 of 18 
"M Srj" wrote in message <jigqp3$f6e$1@newscl01ah.mathworks.com>... 
Thanks Michael for your reply. I run this mfile but got error messages in MATLAB after my data in (theta, R) format: 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 23 Apr, 2012 00:26:06 Message: 4 of 18 
"M Srj" wrote in message <jn22c5$bab$1@newscl01ah.mathworks.com>... 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 23 Apr, 2012 00:44:07 Message: 5 of 18 
"Roger Stafford" wrote in message <jn27iu$h0$1@newscl01ah.mathworks.com>... 
Thanks! It is working now and give me parameters a and b. 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 23 Apr, 2012 21:43:07 Message: 7 of 18 
"M Srj" wrote in message <jn4dlf$i0a$1@newscl01ah.mathworks.com>... 
I used svd function and found U, S, and V. I looked at MATLAB help for "singular value decomposition" but found no clue for finding A, B, ,,,F! 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 24 Apr, 2012 01:43:08 Message: 9 of 18 
"M Srj" wrote in message <jn4slf$h8f$1@newscl01ah.mathworks.com>... 
Subject: fitting curve at polar coordinate From: M Srj Date: 24 Apr, 2012 02:18:06 Message: 10 of 18 
Okey! 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 24 Apr, 2012 05:25:16 Message: 11 of 18 
"M Srj" wrote in message <jn52gu$9vo$1@newscl01ah.mathworks.com>... 
Subject: fitting curve at polar coordinate From: M Srj Date: 24 Apr, 2012 18:54:13 Message: 12 of 18 
Thanks for your helps. 
Subject: fitting curve at polar coordinate From: M Srj Date: 24 Apr, 2012 19:09:13 Message: 13 of 18 
Correction: equation R=a.b/(1+b.sin(theta)) is a general form for conic section by vertical axis of symmetry not only opening downward parabola. 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 24 Apr, 2012 19:11:08 Message: 14 of 18 
"M Srj" wrote in message <jn6ssl$c8q$1@newscl01ah.mathworks.com>... 
Subject: fitting curve at polar coordinate From: M Srj Date: 24 Apr, 2012 20:05:19 Message: 15 of 18 
I already said: "Correction: equation R=a.b/(1+b.sin(theta)) is a general form for conic section by vertical axis of symmetry not only opening downward parabola." which was posted before your reply. You can check this link for above equation: 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 24 Apr, 2012 23:46:24 Message: 16 of 18 
"M Srj" wrote in message <jn711v$2ho$1@newscl01ah.mathworks.com>... 
Subject: fitting curve at polar coordinate From: M Srj Date: 25 Apr, 2012 00:19:22 Message: 17 of 18 
Thanks for all your information. I learnt a lot from your answers. 
Subject: fitting curve at polar coordinate From: Roger Stafford Date: 25 Apr, 2012 02:31:24 Message: 18 of 18 
"M Srj" wrote in message <jn7fua$2fm$1@newscl01ah.mathworks.com>... 
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