how can I put this function by Excel

[SALAH ALATAI]

ASA.png


F(t)= 1/2+2/π (sint+1/3sin3t+1/5sin5t......)

[shg]

Welcome to the board, Salah.

Please take a few minutes to read the forum rules, and then amend your thread title accordingly.

Thanks.

[Crooza]

Hi and welcome. This looks like homework and I'm guessing the moderators are going to be getting onto you about the title too. Once you fix your thread title you might want to explain what part of the assignment you need help with.

[InvisibleMan]

Let's say you put the value 7 in cell A2; you could put this formula in cell B2:

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Copy the sequence down ... A3=8, A4=9, and so on. And then copy the formula down.

[SALAH ALATAI]

Thanks for your response

[alansidman]

Your post does not comply with Rule 1 of our Forum RULES. Your post title should accurately and concisely describe your problem, not your anticipated solution.

Use terms appropriate to a Google search. Poor thread titles, like Please Help, Urgent, Need Help, Formula Problem, Code Problem, and Need Advice will be addressed according to the OP's experience in the forum: If you have less than 10 posts, expect (and respond to) a request to change your thread title. If you have 10 or more posts, expect your post to be locked, so you can start a new thread with an appropriate title.

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[InvisibleMan]

@shg: apologies.

@SALAH ALATAI: please comply with shg's request that you change your thread title to comply with forum rules.

[Crooza]

@alansidman I see the OP has edited his title so I assume you're OK with me posting now. If not kill this post

So this question is more interesting that I first thought and is more complex than @invisibleman's solution because the formula needs to undertake a recurrent calculation of the function (Sin n x t)/n where n = 1,3,5,7,9,11,........... and t is the angle


One way to do this is simply keep adding to the formula below

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note that I've put in A1 the degrees but excel undertakes trig functions in radians so you need to multiply by 2 pi and divide by 360. I put 0 to 360 in column A and copied this down in column B then graphed it on a scatter chart. I'd include the file but for the life of me I can't upload files anymore and yes I've tried all the methods recently posted.

The problem is that you need to make this a very long equation before you get to a level where the incremental change is immaterial. When graphed these all look like squiggly sine curves for the lower end recurrent numbers of n = 5

The trick is to create an array formula that can add up all the SIN(n*A1*2*PI()/360)/n for n = 1,3,5,7,9,11,.......up to a very big number

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The above formula does this nicely and as you can see I chose 1800 just because its a big number and it gives a very nice result at the end of the day (a very square shaped curve)