Search code examples
matlabcurveintersect

Matlab : Intersect point of curves

Say for example I have data which forms the parabolic curve y=x^2, and I want to read off the x value for a given y value. How do I go about doing this in MATLAB?

If it were a straight line, I could just use the equation of the line of best fit to calculate easily, however I can't do this with a curved line. If I can't find a solution, I'll solve for roots

Thanks in advance.

Solution

  • If all data are arrays (not analytical expressions), I usually do that finding minimal absolute error

    x=some_array;
[~,ind]=min(abs(x.^2-y0))

    Here y0 is a given y value

    If your data are represented by a function, you can use fsolve:

    function y = myfun(x)
    y=x^2-y0

[x,fval] = fsolve(@myfun,x0,options)

    For symbolic computations, one can use solve

    syms x
solve(x^2 - y0)