# Find Intersection between curves

2 views (last 30 days)
Anfal AlShehhi on 28 Jun 2022
Commented: KSSV on 28 Jun 2022
In the intersection part
I tried many functions but still couldn't get the right value

KSSV on 28 Jun 2022
This should not dissappoint you.
KSSV on 28 Jun 2022
clc; clear all;
% Defined values
atm=0.17 ; % km-1
xt=2.3; % target (x) in m
yt=2.3; % target (y) in m
p=50/100; % percent target
vis=23; %Visibility in km target
er=26; % LRF
dref=500; % LRF in m
pref=85/100; % LRF
vis2=23; % LRF Visbility
T=90/100; % LRF
sc=1; % LRF
% Range
x=0:0.01:10; % in km
A= exp(-2*atm.*x) ; % Attenuation func
B= ((pref/p)*((x.*x)*1000/dref*dref))*(((exp((-2*atm*dref/1000))*10^(-er/10)))/(T*sc)) ;% Sensi func
L1 = [x;A] ; L2 = [x;B] ;
P = InterX(L1,L2) ;

Sam Chak on 28 Jun 2022
I think the script shared File Exchange works. However, if you want something mathematically simple to understand, you can try fzero(). The approach is similar to what you did previously.
atm = 0.17; % km-1
xt = 2.3; % target (x) in m
yt = 2.3; % target (y) in m
p = 50/100; % percent target
vis = 23; % Visibility in km target
er = 26; % LRF
dref = 500; % LRF in m
pref = 85/100; % LRF
vis2 = 23; % LRF Visbility
T = 90/100; % LRF
sc = 1; % LRF
% Range
x = 0:0.01:10; % in km
A = exp(-2*atm.*x); % Attenuation func
B = ((pref/p)*((x.*x)*1000/dref*dref))*(((exp((-2*atm*dref/1000))*10^(-er/10)))/(T*sc)); % Sensi func
% Plotting two curves initially
plot(x, A, x, B)
ylim([0 1])
% Finding the intersection point
f1 = @(x) exp(-2*atm.*x);
f2 = @(x) ((pref/p)*((x.*x)*1000/dref*dref))*(((exp((-2*atm*dref/1000))*10^(-er/10)))/(T*sc));
f = @(x) f1(x) - f2(x);
x0 = 0.5; % initial guess value (intersection is somewhere near x = 0.5)
xsol = fzero(f, x0)
xsol = 0.4621
ysol = f1(xsol)
ysol = 0.8546
% Markng the intersection point
plot(x, A, x, B), hold on
plot(xsol, ysol, 'mo', 'MarkerSize', 14), hold on
ylim([0 1])

R2022a

### Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!