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JIMRAT
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Sin 30 Equals What?

01/24/2014 8:21 PM

My Sony Xperia smart phone has a scientific calculator function. When I try to use it I get funny results. e.g. sin 30 = -0.988031624.

It has had 2 upgrades and the result is still the same. A colleague has a brand new Sony and gets the same result. I suspect that it is my education that is lacking. Can someone please explain how this works?

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JohnDG
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#1

Re: Sin 30 equals what?

01/24/2014 8:51 PM

You're calculating in radians. You need to select degrees. (Look for "rad" and "deg", probably says "rad" in tiny letters in the display. If you have a button marked "DRG", try it.). Read here for more insight.

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JIMRAT
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#3
In reply to #1

Re: Sin 30 equals what?

01/25/2014 6:13 AM

Thanks John, this calculator has no such buttons. I once made a spreadsheet with Win 85 excel and that could only work in radians. I used it to calculate the length of a hip (for a roof)when the width and pitch were input into a cell (each) but since those days everything I've had to do has been possible with degrees. I still don't understand why it is negative -0.988? I will look at your link for longer and try to work it out from that.

Thanks

Jim

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JohnDG
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#4
In reply to #3

Re: Sin 30 equals what?

01/25/2014 7:38 AM

30 radians = 1718.87339 degrees. So you've "gone round the circle" a few times. Keep taking away 360 until you end up with a number less than 360, and you end up with 278.87339 degrees, and sin(278.87339º)=-0.9880316117

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JohnDG
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#5
In reply to #3

Re: Sin 30 equals what?

01/25/2014 8:10 AM

Suggest you try RealCalc, from Quartic Software. It's available as a free (or very cheap) download, and works in degrees, radians or grads (and has a DRG key!). Usual disclaimers. Other good calculators are available.

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JIMRAT
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#6
In reply to #5

Re: Sin 30 equals what?

01/25/2014 5:48 PM

Light bulb moment!!! Sin (30) is n 30 radians. Thanks again. I have a casio calculator and I am awaiting delivery of a new Casio fx 9860 to play with. The later versions of excel accepted degrees in the formula and so I haven't had much need to use radians. I left school at 15 and learnt maths as a construction tool later in life. I find it useful and challenging but I am by no means proficient.

Thanks, another GA

Jim

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SolarEagle
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#2

Re: Sin 30 equals what?

01/24/2014 9:10 PM

Best to just walk away at this point.....

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ci139
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#7

Re: Sin 30 Equals What?

01/27/2014 9:57 AM

what on earth is a smart phone
we have a proverb that says talking silver staying silent gold
(if i'd combine some more proverbs i'd became a complete idiot - muhahaa)
((((? mute phone - hi hi ?))))

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JIMRAT
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#9
In reply to #7

Re: Sin 30 Equals What?

01/28/2014 5:37 AM

I have to agree. Seen the new quad core smart phones? All I want to do is ring someone. Oh! and take some photos and be able to store notes, and remind when my pills are due to be taken, and show where my destination is and, and, oh damn!

"we have a proverb that says talking silver staying silent gold"

How important is punctuation? Try making sense of this:-

Bill where Bob had had had had had had had had had had had the approval of the teacher.

Jim

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nutwood
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#11
In reply to #9

Re: Sin 30 Equals What?

01/29/2014 5:19 AM

OK, you've got me. Please punctuate and re-post!!

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JIMRAT
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#12
In reply to #11

Re: Sin 30 Equals What?

01/29/2014 5:52 AM

Bill, where Bob had had "had had", had had "had". "Had had" had had the approval of the teacher.

Jim

Thanks to Con ( my english lecturer )

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nutwood
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#13
In reply to #12

Re: Sin 30 Equals What?

01/29/2014 6:02 AM

Love it. Thanks for that!

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tribefan1952
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#8

Re: Sin 30 Equals What?

01/27/2014 9:59 AM

Sin 30 (degrees) = 0.5

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JIMRAT
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#10
In reply to #8

Re: Sin 30 Equals What?

01/28/2014 5:38 AM

Not according to my calculator. It = minus 0.988

Jim

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LongintheTooth
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#14

Re: Sin 30 Equals What?

01/31/2014 4:18 PM

my calculator displays your result of sin of 30 RADIANS.

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JIMRAT
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#15
In reply to #14

Re: Sin 30 Equals What?

02/03/2014 6:59 AM

Thanks, Johndg told me that as well. See post #1

Jim

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