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I have two complicated functions and i plot the contours of them like this:

ContourPlot[{f[x,y]==0,g[x,y]==0},{x,x1,x2},{y,y1,y2}]

I would like to find coordinates of intersection points exactly. I've tried most of solutions people suggested here before line Nsolve or FindRoot but it does not work and i am forced to get the coordinated by decreasing the domain and recognize the intersection point by eye !!! and use 'get coordinates' option !

I would appreciate if anybody helps me. Thanks

vapor
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1 Answers1

3

Example

Code

pts = Solve[y - 2 x^2 + 3/2 == 0 && {x, y} \[Element] Circle[{0, 0}, 1],{x,y}];
parabola = ContourPlot[{y - 2 x^2 + 3/2 == 0}, {x, -1.5, 1.5}, {y, -1.5, 1.5}];
intersections = {Red, PointSize[Medium], Point[{x, y} /. pts]};

Show[{parabola, Graphics[{Circle[{0, 0}, 1], intersections}]}]

Output

example

Reference

Curve Intersection

Show
Solve
ContourPlot
Graphics

e.doroskevic
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  • Dear E.Doroskevic This solution is not suitable for mine.Because if you replace even a simple function like 3 y - 5 x^2 + 7/2 == 0 with Circle[{0, 0}, 1] it does not work. Anyway thank you so much – Noghani Jun 25 '16 at 07:02