i have this two functions how can i plot them together

Question

marwa mhd 2016-4-21

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回答： Brattv 2016-4-21

hallo.png

Length=100000
mu=10
sigma=1
X=sigma*randn(Length,1)+mu; 
plot(X) 
histogram(X) 
grid on 
n=100 
[f,x]=hist(X,n)
bar(x,f/trapz(x,f));hold off; 
g = (1/(sqrt(2*pi)*sigma))*exp(-((x-mu).^2)/(2*sigma^2))
plot(X,g) ;hold on ;grid on

can anyone help me please , i don't where is my mistake , my final output should look like the attached picture

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Answer 1

Brattv 2016-4-21

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https://ww2.mathworks.cn/matlabcentral/answers/280204-i-have-this-two-functions-how-can-i-plot-them-together#answer_218826

在 MATLAB Online 中打开

Hi, Your problem is the last line plot(X,g). You are saying that you have a vector g with 100 point, that you want to plot versus a vector X with 100 000 points. Do the following

Use the histogram bin centers from "x" to find the first and last bin in the histogram. You wanted to plot a function with 100 points, which means that you find the step by finding the difference of the first and last bin and divide by 100.

if true
% Find the first and last valye
plotStep = (x(end) - x(1))/100;
% The steps put into a vector
lengthVect = x(1)+plotStep:plotStep:x(end);
% Plotting.
plot(lengthVect,g) ;hold on ;grid on 
end