Find x-value of cfit function.

Good day, I am trying to find the x-value of a cfit function with a known y-value. I am however struggling as the solve() function doesn't work on the cfit function. I have tried:

g=fit(t,w,'cubicinterp');
plot(g,t,w);

syms tx;
Point=w(1)*0.37;

eqn=Point==g(tx);
solve(eqn,tx);

Where t and w are both 49x1 matrices. I then got the functin g along with the datapoints and plotted them as follows:

If anyone can help me determine the x value for given y-value of the 'g' function help would be much appreciated! Thanks in advance!

Answer 1

[Walter Roberson]

See John's solution at https://www.mathworks.com/matlabcentral/answers/320275-finding-values-from-cubicinterp-fit#answer_250485

[Leon Ellis]

Thanks a lot!