Finding the intersection points between two curves

조회 수: 8 (최근 30일)
raha ahmadi
raha ahmadi 2021년 7월 30일
댓글: Star Strider 2021년 8월 7일
I need to find the intersection points of this equation:
this is my code. I dont know what is the best way . Also when I plot in terms of I have some periods but when I plot in terms of β I have only one period. How I can plot it in terms of beta but with nulti perids?
many thanks in advance
h=20;
K=13.6;
l=1148e-6;
g1=fplot(@(beta)tan(beta*l));
hold on
g2=fplot(@(beta)2*h*beta*K/(K^2*beta^2-h^2));
Warning: Function behaves unexpectedly on array inputs. To improve performance, properly vectorize your function to return an output with the same size and shape as the input arguments.

채택된 답변

Star Strider
Star Strider 2021년 7월 30일
Several options —
h=20;
K=13.6;
l=1148e-6;
f1 = @(beta)tan(beta*l);
f2 = @(beta)2*h*beta*K./(K^2*beta.^2-h^2);
figure
g1 = fplot(f1);
hold on
g2 = fplot(f2);
g3 = fplot(@(beta) f2(beta)-f1(beta), '--'); % Use 'fsolve' On 'g3' To Find The Intersections
Another option:
format long
Xint = interp1(g3.YData, g3.XData, 0)
Xint =
0
.
  댓글 수: 11
raha ahmadi
raha ahmadi 2021년 8월 7일
your answer is perfect. I m really appresiate.
hope you all the best
Star Strider
Star Strider 2021년 8월 7일
Thank you!
As always, my pleasure!
.

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추가 답변 (1개)

darova
darova 2021년 7월 30일
I'd try fsolve for solving
Read help carefully:
fplot(f,[0 10])
  댓글 수: 1
raha ahmadi
raha ahmadi 2021년 7월 30일
편집: raha ahmadi 2021년 7월 30일
Dear darova
Thank you for your help, I read fsolve but I think it solves a system of nonlinear equations. I used fzero instead but I only got one answer I need solve it in some periods and get more roots
Best regards

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