Numbers and Calculator give different values for sine and cosine of number

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Level 3

743 points

Numbers and Calculator give different values for sine and cosine of number

If I enter =SIN(30) (that's 30 degrees) and press return in Numbers I get -0.988031624092862. If I enter 30 in Calculator and press SIN I get 0.5, which is what I learned it was..

Does anyone know why this is?

Thanks

Power Mac Dual 1.4GHz G4; iMac Core 2 Duo, Mac OS X (10.5.6), 2GB Ram, SATA RAID external drives; 1GB Ram

Posted on Sep 23, 2009 8:43 AM

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Answer 1

James Mol Author

Level 3

743 points

Sep 23, 2009 11:01 AM in response to Badunit

That's right, when I entered it from the Function Browser it came up as you stated. We agree on that.

But the part that threw me was the (radian-angle). Here I was thinking triangles and degrees, and the equation talks about radians - hadn't thought about radians for some 35 years, I couldn't figure out why that would even be part of the equation. But what do I know.

Thanks for the example, as was listed in the formula guide example 2. I see from example 1 that I should expect the sin of the radian if I just answer the number.

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Answer 2

KOENIG Yvan

Level 8

41,825 points

Sep 23, 2009 12:49 PM in response to James Mol

James Mol wrote:
Doh,

I just typed "sin" in the help search without reading the rest of the menu first, and as you already know, any reference to the iWork Formulas and Functions Guide was no longer listed.

Now that I have gone back and deleted the search I see it in plain sight.

Since you are well read on the subject, maybe you could answer why sine of 30 on the calculator equals the sine of 30 degrees but not on the computer.

Simply because you asked the Calculator to use degrees.

There is a button at its left bottom to switch between Degrees and Radians.

For mathematicians, the logical unit for angles is Radian. I assume that it's why Spreadsheets use it.

I don't have a lot of time on spread sheets and even less on programing, why can't the worlds greatest computer with the worlds easiest to use interface, and an easy to use spreadsheet, let a dummy like myself, get the sine of 30 degrees by simply putting =SIN(30)? Why do I have to put in the RADIANS when I want the answer for degrees?

Use the correct syntax which is

=SIN(RADIANS(30))
and you will get what you want.

Every tool requires a learning curve.

You learnt to speak
You learnt to walk
…
Using a computer is not a natural ability.
We have to learn how to.

It kind of reminds me of the Polish notation on the first HP calculators, but then again, I never did understand that either.

Happily, the _Reversed Polish Notation_ (RPN) is always in use.
It's available with the Apple Calculator .
Its more efficient than the current one when we are accustomed to its use.

Opps, forgot the S on Radians - even when I read I don't see all I should.

One radian, ∏ radians.
So the s is required when we have several radians, not if we have one or less than one of them 😉

Yvan KOENIG (VALLAURIS, France) mercredi 23 septembre 2009 21:48:34

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Answer 3

KOENIG Yvan

Level 8

41,825 points

Sep 23, 2009 8:56 AM in response to Badunit

Hi badunit

Are you sure that users read the iWork Formulas and Functions User Guide which every one may download from the Help menu ?

I feel that most of them don't and prefer ask here to those who took time to read 😟

Yvan KOENIG (VALLAURIS, France) mercredi 23 septembre 2009 17:56:01

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Answer 4

James Mol Author

Level 3

743 points

Sep 23, 2009 11:29 AM in response to KOENIG Yvan

Doh,

I just typed "sin" in the help search without reading the rest of the menu first, and as you already know, any reference to the iWork Formulas and Functions Guide was no longer listed.

Now that I have gone back and deleted the search I see it in plain sight.

Since you are well read on the subject, maybe you could answer why sine of 30 on the calculator equals the sine of 30 degrees but not on the computer.

I don't have a lot of time on spread sheets and even less on programing, why can't the worlds greatest computer with the worlds easiest to use interface, and an easy to use spreadsheet, let a dummy like myself, get the sine of 30 degrees by simply putting =SIN(30)? Why do I have to put in the RADIANS when I want the answer for degrees?

It kind of reminds me of the Polish notation on the first HP calculators, but then again, I never did understand that either.

Just like to know why.

Thanks for looking at my post, I will try to read first and ask questions later next time.

Opps, forgot the S on Radians - even when I read I don't see all I should.

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Answer 5

Badunit

Level 7

30,984 points

Sep 23, 2009 1:06 PM in response to James Mol

James Mol wrote:
It kind of reminds me of the Polish notation on the first HP calculators, but then again, I never did understand that either.

Yes, RPN has a learning curve. Or, more accurately, a "remembering to do it a different way" curve. All I ever use is RPN calculators, except when forced by circumstances to do otherwise.

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Answer 6

Badunit

Level 7

30,984 points

Sep 23, 2009 8:52 AM in response to James Mol

The function is clearly stated in the formulas guide and the function browser as SIN(radian-angle)

Use SIN(RADIANS(30))

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