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abhi_iitian, Computer Software Engineer
Category: Programming
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Experience:  B-Tech Topper in CSE from IIT Roorkee, Experience as S/W design Engineer at Microsoft India
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# in excel how do I convert polar back to rectangular

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in excel how do I convert polar back to rectangular
Hello and welcome to just answer.

I and other experts will get on to solve your problem. Could you help us by providing the following information :

Could you elaborate your problem as to what do you want and what is not happening ?

Are you drawing a chart where you want rectangular instead of polar or do you just want to simply convert from polar to rectangular ?

Also, you could upload the excel file here and when the upload completes, you will get a download link, post that in your next post so that I can correct the problem with that.

Thanks

Hi, Sorry I missed the already tried portion of your post.

To convert from polar to rectangular coordinates, say you have in polar (r, theta)

Then in rectangular it becomes (r cos(theta) + r sin(theta) j)

So if we have 24.237-37.972 polar

then its rectangular will be

( 24.237cos(-37.972) + 24.237 sin(-37.972) j)

Now you can use these formula to convert from polar to rectangular coordinates

x = r cos (theta)

y = r sin (theta)

so rectangular coordinates become (r cos(theta) + r sin(theta) j)

Now excel expects the angle to be in radian, so if your angle is in degree, you will have to use excel's RADIANS function to convert the degree angle into radian and then use the cos formula,

So the formula will be x = r * cos (RADIANS(theta))

y= r * sin(RADIANS(theta))

Let me know if there are any doubts

Customer: replied 8 years ago.
Sorry but my internet is playing up. have tried your answer and whilst the results are close to the correct answer they are not the same. Could you please enter my figures into excel at your ens and see if you get the correct answer. If so I must be entering the formulas incorrectly. Thanks Dave
Hi there, When I do this in my excel for ,
24.237-37.972 polar and the answer is 19.11-14.91j rectangular
say I have columns as

A B C = A1 * cos(RADIANS(B1) D = A1 * sin(RADIANS(B1)
24.237 -37.972 19.10631 -14.9125

I hope you are getting same answer.

Now you say answer is 19.11-14.91j rectangular right which is actually the value we have got from excek rounded up to 2 decimal places,
If we want rounded up to 2 decimal places, we can use the ROUND funstion in excel
SO For rounding up to 2 decimal places, the formula will be

Hope that helps.
Customer: replied 8 years ago.

I am really sorry but I cannot get my head around this - plus I am an oldie (65 years) so its probably very simple.

Can you put the figures into the formula for me - for example =24.237*cos(RADIANS(37.972)) IS THAT CORRECT???

Thanks for being there - you are working late???

Do not worry , I will assist you till you get it :
You have 24.237-37.972 polar
Is there a minus sign or not with 37.972

If there is no minus sign it is

24.237*cos(RADIANS(37.972)) as you said

which gives the value 19.10631 , did you get this value or not ??

Now 19.10631 when rounded to 2 decimal places, give us 19.11 which is what is needed as the answer.

To get this directly from excel you will need the formula

Let me know at which step you are having trouble ? Tell me what answers you get.

if there is a minus sign iwith 37.972 it will be - 37.972

Customer: replied 8 years ago.
Well it looks like I have typed it in correct - but my Excel gives me 19.3352 - this is why I questioned it - so is there a difference in versions of excel? when we get this correct - can I ask one other Q or do I have to start a new thread? regards Dave
Well, that is very strange to me that it is giving slightly incorrect results to you. I have tried in Excel 97- 2003 format and Excel 2007. Which version do you have ?

Make sure that there is no typographical error and you are entering the exact formula in excel that is =24.237*COS(RADIANS(37.972))

Or are you using the formula with some other values which are getting calculated by some other formula and using them in this formula instead of (24.237, 37.972).
The case may be that you are thinking that they are (24.237, 37.972) but they are actually slightly different and hence the result

If you have a excel sheet and nothing private and you want me to look into it you can upload it, You could upload the excel file here and when the upload completes, you will get a download link, post that in your next post so that I can correct the problem with that.

You can ask another question if it is related to this one here itself or you can ask it in a separate thread as it would get more attention.
Customer: replied 8 years ago.
You are correct it was a mistake in my original data - so I am happy. the other question is this - I have 2 cells resulting in 24.2373 in one sell and 37.972 in the other - is there any way I can automatically combine these into one cell resulting in 24.2373+37.972j so that further calculations can be made on the one cell.Regards Dave
Hi,

You can use the COMPLEX function is excel to convert this (x,y) in (x+yj) form

Syntax

COMPLEX(real_num,i_num,suffix)

Real_num is the real coefficient of the complex number.

I_num is the imaginary coefficient of the complex number.

Suffix is the suffix for the imaginary component of the complex number. If omitted, suffix is assumed to be "i".

So in our case suppose we have the x data in E4 and y data in G4, we will have to use

=COMPLEX(ROUND(E4,2),ROUND(G4,2),"j")

=COMPLEX(ROUND(24.2373,2),ROUND(37.972,2),"j")

this will give the result as

24.24+37.97j

to get it into that format, ROUND is needed since complex function by default converts data into 15 decimal places and that does not look good.

If you do not want even those 2 intermediary columns for x and y , you can use

but that becomes a bit complicated.

Also, once you convert into complex , you will need to use complex number functions to get real (x) and imaginary (y) part from that value or to perform any further calculation

Hope that helps.

abhi_iitian and 2 other Programming Specialists are ready to help you
Customer: replied 8 years ago.

OK you have been Excellent - I will not ask further on the second Q as you have given me a good pointer to get it working.

If I need you again after I have accepted how do I get back to you - Dave

Hello Dave,

Thanks for your compliment.

If you need me again after accepting, you can write "For Abhi" in the question title and/or request for me while asking the question initially.

Thanks and have a nice day !!