Why am I getting zeros

%Latty:
38
39
37
40
39
36
39
39
38
40
35
37
38
40
40
37
36
36
39
36
40
35
39
35
39
39
35
38
39
38
37
36
35
37
39
40
36
39
39
38
38
36
36
38
36
36
38
35
40
36
36
36
36
37
38
39
36
35
38
40
36
32
Latty=LLARYP.Lat;
a=6378137; %meters
b=6356752; %Meters
fprintf ("Prime Vertical Radius of Curvature\n");

i = 1;
sz = size(Latty);
while i <= sz(1)
    Rn(:,1)=(a^2)/(sqrt((a^2)*(cosd(Latty).^2)+(b^2)*(sind(Latty).^2)));
    i = i + 1;
end
fprintf("Rn =");
disp (Rn)


%Output
Prime Vertical Radius of Curvature
Rn =   1.0e+06 *

         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
         0
    6.3841



%%The output I get

Answer 1

[Voss]

Latty = [38; 39; 37; 40; 39; 36; 39; 39; 38; 40; 35; 37; 38; 40; 40; 37; 36; 36; 39; 36; 40; 35; 39; 35; 39; 39; 35; 38; 39; 38; 37; 36; 35; 37; 39; 40; 36; 39; 39; 38; 38; 36; 36; 38; 36; 36; 38; 35; 40; 36; 36; 36; 36; 37; 38; 39; 36; 35; 38; 40; 36; 32];
a=6378137; %meters
b=6356752; %Meters

Your while loop doesn't appear to be necessary; it's performing the exact same calculation multiple times. Maybe you meant this:

i = 1;
sz = size(Latty);
while i <= sz(1)
    Rn(i,1)=(a^2)/(sqrt((a^2)*(cosd(Latty(i)).^2)+(b^2)*(sind(Latty(i)).^2)));
    i = i + 1;
end
disp(Rn)

   1.0e+06 *

    6.3862
    6.3866
    6.3859
    6.3870
    6.3866
    6.3855
    6.3866
    6.3866
    6.3862
    6.3870
    6.3852
    6.3859
    6.3862
    6.3870
    6.3870
    6.3859
    6.3855
    6.3855
    6.3866
    6.3855
    6.3870
    6.3852
    6.3866
    6.3852
    6.3866
    6.3866
    6.3852
    6.3862
    6.3866
    6.3862
    6.3859
    6.3855
    6.3852
    6.3859
    6.3866
    6.3870
    6.3855
    6.3866
    6.3866
    6.3862
    6.3862
    6.3855
    6.3855
    6.3862
    6.3855
    6.3855
    6.3862
    6.3852
    6.3870
    6.3855
    6.3855
    6.3855
    6.3855
    6.3859
    6.3862
    6.3866
    6.3855
    6.3852
    6.3862
    6.3870
    6.3855
    6.3841

However, you can do the same thing without a loop. (Use ./ for element-wise division.)

Rn = a^2./sqrt(a^2*cosd(Latty).^2+b^2*sind(Latty).^2);
disp(Rn)

   1.0e+06 *

    6.3862
    6.3866
    6.3859
    6.3870
    6.3866
    6.3855
    6.3866
    6.3866
    6.3862
    6.3870
    6.3852
    6.3859
    6.3862
    6.3870
    6.3870
    6.3859
    6.3855
    6.3855
    6.3866
    6.3855
    6.3870
    6.3852
    6.3866
    6.3852
    6.3866
    6.3866
    6.3852
    6.3862
    6.3866
    6.3862
    6.3859
    6.3855
    6.3852
    6.3859
    6.3866
    6.3870
    6.3855
    6.3866
    6.3866
    6.3862
    6.3862
    6.3855
    6.3855
    6.3862
    6.3855
    6.3855
    6.3862
    6.3852
    6.3870
    6.3855
    6.3855
    6.3855
    6.3855
    6.3859
    6.3862
    6.3866
    6.3855
    6.3852
    6.3862
    6.3870
    6.3855
    6.3841

[olivia]

wow thank you so much

[Voss]

You're welcome!