x and y intercepts
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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.
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Answers (2)
Jos (10584)
on 3 Jul 2014
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.
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Jos (10584)
on 4 Jul 2014
so, what model does fit your data? Perhaps you can also take a look at interp1 or zero to find the intersections.
Star Strider
on 3 Jul 2014
Without seeing your data I can only speculate, but using the interp1 function with the 'linear','extrap' options could do what you want.
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