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I have a problem with plotting a summation equation, Help me!

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DIEGO PACHECO
DIEGO PACHECO on 11 Jan 2020
Commented: DIEGO PACHECO on 14 Jan 2020
The question: For the fuction:
I tried as described below, but failed. I hope to help from you. Thanks.
k=6; %scalar, example
def f(k,x): return sum( sqrt((2*k-3)/((3+i)*(2*k-4-i))) for i in range(x+1))
plot(f(k,x) for x in range (2*k-8) )

Accepted Answer

Meg Noah
Meg Noah on 11 Jan 2020
Edited: Meg Noah on 12 Jan 2020
Hi.
Editing - I had a (3-i) instead of (3+i) in the denominator - it's fixed now:
k = 6;
f = @(x)sum(sqrt((2*k-3)./((3 + [0:(x+1)]).*(2*k-4-[0:(x+1)]))));
x = 0:(2*k-8);
y = zeros(size(x));
for j = 1:length(x)
y(j) = f(x(j));
end
plot(x,y,':+');
hold on;
title(['f(k,x) where k = ' num2str(k)]);
ylabel('f(k,x)'); xlabel('x');
legend('location','southwest');
strangePlot.png

More Answers (1)

David Hill
David Hill on 11 Jan 2020
k=6;
f=zeros(1,2*k-7)
for i=0:2*k-8
f(i+1)=sqrt((2*k-3)/((3+i)*(2*k-4-i)));
end
f=cumsum(f);
f=f(1:2:end);%x=0,2,4
plot(f);

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