MATLAB help with function and while loop?

Whenever I try to call this function, I get the error: Subscript indices must either be real positive integers or logicals. Any help?

[Daniel kiracofe]

Your code looks okay to me. I don't see anything wrong off the top of my head. Suggest that you take a look at points #3 and 5 in the below and add more detail.

https://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

Answer 1

[Roger Stafford]

I see at least four difficulties in your code:

a) You shouldn’t use the word ‘sum’ for a variable. Matlab has a function by that name and this function expects an argument. Use some other name.

b) The series you describe does not converge to e. Probably it is 1/k! = 1/factorial(k) that you are thinking of.

c) The variable ‘answer’ remains at a constant value of 1, not e, so your while loop would never stop, (once you correct the above a) error.)

d) In the line:

   term = sum+1/k^2;

the variable 'term' would not be the next term but would be the partial sum and therefore the next line would be totally incorrect:

   sum = sum+term;

It would amount to calculating the cumulative sum of partial sums - something you certainly don't want. Correction: No, it would actually amount to a kind of doubling of partial sums at each step. It would very soon overflow matlab's maximum possible numerical value, 'realmax', which is a terrifically large number.

Addendum: The sum of the infinite series 1/k^2 would actually give you pi^2/6. To show this, look up the definition of the first Bernoulli number, B1, and its value.