# plotting using if and for loop

2 views (last 30 days)
mhya k on 13 Jun 2022
Edited: mhya k on 13 Jun 2022
Hello,
I should programming this formula and plot the picture (pic1) in below with these condiction (pic2) but when I run my code it didn't give me any curve and since I didn't get any I only write first formula in here.
it would be great if someone can help me.
my code ;
close all;
clc;
clear all;
x=0:0.01:pi/2;
n2=1.5;
n1=1;
n=n1/n2;
C = asin(n);
P = atan(n);
B= sqrt((sin(x)^2 - (n^2));
D = (n^2)*cos(x);
y1=180;
y2=0;
y3= 2*atan(B/D);
z=zeros(1,length(x));
for j=1:length(x);
if (x(j) < C);
z(j)=y1(j);
elseif (x(j)>C) && (x(j)<P);
z(j)=y2(j);
else
z(j)=y3(j);
end
end
i=x*180/pi;
plot(i,z)

Ganesh on 13 Jun 2022
The issue seems to be 3 things.
a) The elements aren't dot squared(line 10)
b) y1, and y2 are integers but are indexed(only arrays and other such data types can be indexed)
c) Inconsistency between radians and degrees(z hasnt been converted to degrees)
The below code fixes the issues in order to plot Theta(tm).
close all;
clc;
clear all;
x=0:0.01:pi/2;
n2=1.5;
n1=1;
n=n1/n2;
C=asin(n);
P=atan(n);
B=sqrt(sin(x).^2 - (n^2));
D=(n^2)*cos(x);
y1=pi;
y2=0;
z=zeros(1,length(x));
for j=1:length(x);
if (x(j) < P);
z(j)=y1;
elseif (x(j)>P) && (x(j)<C);
z(j)=y2;
else
z(j)=2*atan(real(B(j)/D(j)));
end
end
i=x*180/pi;
z=z*180/pi;
plot(i,z)
mhya k on 13 Jun 2022
Edited: mhya k on 13 Jun 2022
omg thank you it worked. really thank for your help.

### Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

R2021b

### Community Treasure Hunt

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

Start Hunting!