Problem with IF statement

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Fe99
Fe99 el 27 de Nov. de 2020
Comentada: Rik el 27 de Nov. de 2020
why doesn't it give me a result if I enter " if D == l " I wan't to calculate all initial velocities and angles at which the length is 100m.
clear all
close all
clc
%1
v0 = [15:0.001:60]; %initial velocity
kot = [15:60]; %angle
g = 9.81; %gravity
l = 100; %distance
for i = 1:length(v0)
for j = 1:length(kot)
D = (v0(i)^2*sind(2*kot(j)))/g; %distance
if D == l
fprintf('Vo = %.2f m/s | kot = %.2f° | D = %.2f \n',v0(i),kot(j), D);
end
end
end

Respuestas (1)

Rik
Rik el 27 de Nov. de 2020
Don't use clear all. You don't need it.
I suspect you encountered the wondrous world of floats. Computers don't have infinite memory and may round numbers in ways that you don't expect. This is especially a problem if you are asking for exact equality, while you would be satisfied with equality within machine precision.
Instead of a==b use abs(a-b)<tol. You can use the eps function, or set another value.
  4 comentarios
Fe99
Fe99 el 27 de Nov. de 2020
sorry my bad. thanks for answer
Rik
Rik el 27 de Nov. de 2020
No problem. If my answer solved your question, please consider marking my answer as accepted answer. If not, feel free to comment with your remaining issues.

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