HELP! how to use matlab or excel to solve a curve equationas title. I got standard curve data. According to the data sheet, I shall get a curve like sin or cos. Y-axis is normal, X-axis is log axis.
I need to solve out the curve equation so that I can calc my results.
urgent. help. thank you[longbow1287 (1-31 15:16, Long long ago)] [ 传统版 | sForum ][登录后回复]1楼

do you meando you mean: "you have a set of points (x1,y1), (x2,y2), ..., (xn,yn). you want to find a function y=f(x) such that all the points are close to the curve of y=f(x)"?[吴永铮 (2-1 12:35, Long long ago)] [ 传统版 | sForum ][登录后回复]2楼

(引用 吴永铮:do you meando you mean: "you have a set of points (x1,y1), (x2,y2), ..., (xn,yn). you want to find a function y=f(x) such that a...)yes. this is what I mean.[longbow1287 (2-5 13:50, Long long ago)] [ 传统版 | sForum ][登录后回复]3楼

(引用 longbow1287:yes. this is what I mean.)Matlab SolutionWell, I am still not sure what you want to do according to your problem statement. But generally for data-fitting, you shall
First, propose the model first (i.e. maybe in this case your sine or cosine function or whatever, for example y=AsinBx+C), use Matlab function nlinfit to find best parameter set (A,B,C);
Second, use Matlab function nlparci to find confidence interval for A,B&C respectively;
Finally, use chi2test to evaluate your model based on best-fit (A,B,C) from nlinfit. If not satisfied, propose a new model.[3121 (2-6 11:02, Long long ago)] [ 传统版 | sForum ][登录后回复]4楼