2nd degree fit with x^2 unknown

Hi, i want to make a curv fit to this eq: t=r^2*x^2+t(1) where r and t are known and vectors ( r=[0 2.1 4.2 6.3 8.4 10.5 12.6 ]

t =[93.3168 0 91.1868 0 93.0526 91.9160 88.0559] ) and then get x. I also want to exclude the values where t=0 and their corresponding r. Anyone that knows how to? Ive been searching forever but all functions asunme that i plug in x and y and want the coefficients but thats not the case here!

Thanks allot!!

Answer 1

[bym]

If r & t are known, you can solve for x - no curve fitting required

clc;clear
t = [93.3168 0 91.1868 0 93.0526 91.9160 88.0559];
r = [0 2.1 4.2 6.3 8.4 10.5 12.6 ];
r = r(t~=0);  %discard r where t = 0
t = t(t~=0);  %discard t = 0
x = sqrt((t-t(1))./r.^2)

[emelie Flood]

<hi! Thanks for the answer, the thing is though that i want the x that fits the curve the best, only one x and not a vector! anyone knows how to do this?

<thanks allot!!

/Emelie