Summation, Please help i will buy you a cookie :D
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I thought i had figured out summation, but apparent not :( I have a text book question that asks " evaluate series Σ Un (to infinity, with n=1) and Un is not known." The book gives you Un+1 = (Un)^2 with U1 = 0.5. Stop summation at Un < 10^-8 My code i wrote myself is
n = 2;
v = 10^-10
for ii = 0.5:length(v);
sum= (ii)^n;
end;
disp(sum)
Why does it not work....please help! :D
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採用された回答
Kevin Claytor
2014 年 2 月 11 日
Let's break it down into some steps. First consider the problem for a moment;
We have the series U(n+1) = U(n)^2, U(1) = 0.5
By hand we can tell that the next few terms in the series are; U(2) = .5*.5 = 0.25, U(3) = .25*.25 = 0.0625, U(4) ~= 0.0039, ...
Here's a question for you: How can we get these numerically? Can you give me a for-loop that computes each of these?
Now, the next condition is deciding when to stop. Since we are computing the sum, we are going to stop when we end up adding very small terms. Hence we'll get an approximate answer. We've decided that this will be when U(n) < 10^(-8). Perhaps we can check this condition with an if or a while statement? Can you give an example of one of these?
If you can implement these two parts, I think you will see the answer.
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その他の回答 (1 件)
Azzi Abdelmalek
2014 年 2 月 11 日
Have you checked the length of v?
Don't use sum as variable (sum is a Matlab built-in function)
When you write
a=10
a=20
a=1
What is the final result?
3 件のコメント
Azzi Abdelmalek
2014 年 2 月 11 日
編集済み: Azzi Abdelmalek
2014 年 2 月 11 日
Have you checked the length of v?
Don't use sum as variable (sum is a Matlab built-in function)
What your for loop is doing?
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