whenever i use individual value of time (Tv) the output function (F) giving right value but using time in the form of loop ,output function gives wrong result for all.How to fix this ?

Question

Sarvjeet Singh 2020-9-29

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/602038-whenever-i-use-individual-value-of-time-tv-the-output-function-f-giving-right-value-but-using-ti

评论： Sarvjeet Singh 2020-10-2

采纳的回答： Alan Stevens

clc

clear all

c1 = 3.742*10.^8;

c2 = 1.43878*10.^4;

sigma = 5.67*10.^-8;

lamda_1 = 8;

lamda_2 = 13;

Tv = -10:5:30;

F = zeros(size(Tv));

count = 1;

for T=Tv

fun = @(lambda) c1./(lambda.^5.*(exp(c2./(lambda * T+273)))-1);

F(count) = integral(fun,lamda_1,lamda_2)./(sigma.*(T+273)^4)

plot(T, F(count), '+', 'MarkerSize', 10, 'LineWidth', 2)

hold on

grid

count = count + 1;

end

xlabel('Temperature')

ylabel('Fraction in atmospheric window)')

title('Fraction of the radiation emitted in the atmospheric window as a function of temperature')

legend('T=-10','T=-5','T=0','T=5','T=10','T=15','T=20','T=25','T=30')

hold off

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Answer 1

Alan Stevens 2020-9-29

1
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在 MATLAB Online 中打开

You missed a set of brackets connecting TV to 273.

c1 = 3.742*10.^8;
c2 = 1.43878*10.^4;
sigma = 5.67*10.^-8;
lamda_1 = 8;
lamda_2 = 13;
Tv = -10:5:30;
F = zeros(size(Tv));
count = 1;
for T=Tv
fun = @(lambda) c1./(lambda.^5.*(exp(c2./(lambda *(T+273))))-1); %%%%%%%
F(count) = integral(fun,lamda_1,lamda_2)./(sigma.*(T+273)^4);
plot(T, F(count), '+', 'MarkerSize', 10, 'LineWidth', 2)
hold on
count = count + 1;
end
grid
xlabel('Temperature')
ylabel('Fraction in atmospheric window)')
title('Fraction of the radiation emitted in the atmospheric window as a function of temperature')
legend('T=-10','T=-5','T=0','T=5','T=10','T=15','T=20','T=25','T=30')
hold off

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Alan Stevens 2020-9-30

在 MATLAB Online 中打开

Or, if you don't want the crosses at all:

c1 = 3.742*10.^8;
c2 = 1.43878*10.^4;
sigma = 5.67*10.^-8;
lamda_1 = 8;
lamda_2 = 13;
Tv = -10:30;
F = zeros(size(Tv));
count = 1;
for T=Tv
fun = @(lambda) c1./(lambda.^5.*(exp(c2./(lambda *(T+273))))-1); 
F(count) = integral(fun,lamda_1,lamda_2)./(sigma.*(T+273)^4);
count = count + 1;
end
plot(Tv,F)
grid
xlabel('Temperature')
ylabel('Fraction in atmospheric window)')
title('Fraction of the radiation emitted in the atmospheric window as a function of temperature')