x and y intercepts

from a set of data points how can i find the x and y intercepts. These points are not amoung the data points so i can't use 'data cursor' tool here.

Answer 1

[Jos (10584)]

You want to fit a line to your x,y points and then solve the fitted line for y is zero and x is zero, giving you the x- and y-intercept. For instance, assuming your points are well-fitted by a straight line:

P = polyfit(X,Y,1)
Yintercept = P(2) 
Xintercept = -P(2) / P(1)

For a higher-order polynomial fit, the Y intercept is still the last element of P, but finding the Xintercept (if it exists) is less straightforward.

[Neethu]

Thanks for your answer but my data points cannot be fitted by a straight line ,its the IV curve of a solar cell.

[Jos (10584)]

so, what model does fit your data? Perhaps you can also take a look at interp1 or zero to find the intersections.

Answer 2

[Star Strider]

Without seeing your data I can only speculate, but using the interp1 function with the 'linear','extrap' options could do what you want.