Question on Standard form

PhoenixFire · 05-03-2007, 10:30 AM

In some Maths homework, I came across a slight problem when using Standard form.

The answer to a question was 29.7867*10^(-1)
Becuase I know you can't have a correct Standard Form number starting with a number that is <10, so I remembered that you move the decimal place one place to the left, so that the number ended up being 2.978768*10^(???)
The problem is, is that I don't know what to put the index number (or power) as, because it is near to 0.

Anyone who can help?

Neil Pickup · 05-03-2007, 10:39 AM

A number x10^(-1) is a number multiplied by 0.1 - seeing as 10^(-1) = 1/(10^1) = 1/10 = 0.1
So your number is 29.7 x 0.1 = 2.97

You're right, a standard form answer must start with a number between 1 and 9.999 - so you need to adjust the second part of the SF number to reflect that. 2.97 x 10^(?) = 2.97

Clearly the answer to [10^(?)] needs to be 1 in order for the calculation to balance - and anything to the power of zero is 1.

29.7x10^(-1) = 2.97x10^0
---

Another way of looking at it is that you have divided the left-hand part of the calculation by ten, so you must multiply the right-hand part by the same amount to keep its value constant.

PhoenixFire · 05-03-2007, 10:42 AM

Cheers Neil, all's good.

marc71178 · 05-03-2007, 10:43 AM

IIRC 10^(-1) is the same as 1/10.

So the answer would be 2.97867

PhoenixFire · 05-03-2007, 10:45 AM

So no need for Standard Form in the answer then?

Neil Pickup · 05-03-2007, 10:49 AM

Depends if the question asks specifically for an answer in standard form or not!

PY · 05-03-2007, 11:35 AM

To doubly complicate things, you have engineering standard form which asks for the exponential to be of the order of three i.e. milli, micro, kilo, mega, giga etc.

I'd leave it without the standard form unless it explicitly asks for it.

Tom Halsey · 05-03-2007, 11:38 AM

Fairly quality idea, never thought of asking fellow CWers to do my homework for me.

PhoenixFire · 05-03-2007, 11:38 AM

Gah, I hated those prefixes. We had to work out how many Mega-Seconds equated to 1.98 Giga-Hours, nastily difficult.

PhoenixFire · 05-03-2007, 11:39 AM

Quote:

Originally Posted by Tom Halsey

Fairly quality idea, never thought of asking fellow CWers to do my homework for me.

I usually ask Neil or Turd tbh.

Turns out that Turd is a bit of a wizz at Algebra.

open365 · 05-03-2007, 12:00 PM

Is anyone a whiz at writing film reviews or Spanish coursework?Anyone?Please?

PhoenixFire · 05-03-2007, 12:01 PM

Quote:

Originally Posted by open365

Is anyone a whiz at writing film reviews or Spanish coursework?Anyone?Please?

Tomm NCCC · 05-03-2007, 01:52 PM

Quote:

Originally Posted by open365

Is anyone a whiz at writing film reviews or Spanish coursework?Anyone?Please?

If I had time I would like to try my hand at reviewing films, when is it due?

open365 · 05-03-2007, 02:02 PM

Quote:

Originally Posted by Tomm NCCC

If I had time I would like to try my hand at reviewing films, when is it due?

Last Monday.

Matteh · 05-03-2007, 02:05 PM

Quote:

Originally Posted by open365

Is anyone a whiz at writing film reviews or Spanish coursework?Anyone?Please?

If it was German coursework then i could help, or Pitt could help if it was French. You've picked a dire language i'm afraid.

05-03-2007, 10:39 AM	#2 (permalink)
Neil Pickup Cricket Web Staff Member / Global Moderator Join Date: Mar 2002 Location: Oxford, England Posts: 26,361	A number x10^(-1) is a number multiplied by 0.1 - seeing as 10^(-1) = 1/(10^1) = 1/10 = 0.1 So your number is 29.7 x 0.1 = 2.97 You're right, a standard form answer must start with a number between 1 and 9.999 - so you need to adjust the second part of the SF number to reflect that. 2.97 x 10^(?) = 2.97 Clearly the answer to [10^(?)] needs to be 1 in order for the calculation to balance - and anything to the power of zero is 1. 29.7x10^(-1) = 2.97x10^0 --- Another way of looking at it is that you have divided the left-hand part of the calculation by ten, so you must multiply the right-hand part by the same amount to keep its value constant. __________________ MSN Messenger: minardineil2000 at hotmail dot com \| AAAS Chairman CricketWeb Black \| CricketWeb XI Captain ClarkeWatch: We're Watching Rikki - Are You? Up The Grecians - Exeter City FC Completing the Square: My Cricket Web Blog

05-03-2007, 10:43 AM	#4 (permalink)
marc71178 Eyes not spreadsheets Join Date: Nov 2001 Location: England Posts: 56,346	IIRC 10^(-1) is the same as 1/10. So the answer would be 2.97867 __________________ marc71178 - President and founding member of AAAS - we don't only appreciate when he does well, but also when he's not quite so good! Anyone want to join the Society? Beware the evils of Kit-Kats - they're immoral apparently.

05-03-2007, 11:35 AM	#7 (permalink)
PY International Coach Join Date: Jan 2003 Location: Midlands, UK Posts: 10,736	To doubly complicate things, you have engineering standard form which asks for the exponential to be of the order of three i.e. milli, micro, kilo, mega, giga etc. I'd leave it without the standard form unless it explicitly asks for it. __________________ A True Champion - Bob. Rest in peace. 15/04/06 "People today have too big a devil and too small a God" - Stephen Currie "The Lord is my light and my salvation; whom shall I fear? The Lord is the strength of my life; of whom shall I be afraid?" Psalm 27:1

05-03-2007, 11:38 AM	#8 (permalink)
Tom Halsey International Coach Join Date: Nov 2003 Location: Halsway, CW Land Posts: 12,697	Fairly quality idea, never thought of asking fellow CWers to do my homework for me. __________________ MSN - tomhalsey123@hotmail.com Manchester United FC: 20 Times R.I.P. Sledger's Signature, 2004-2008

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05-03-2007, 10:42 AM	#3 (permalink)
PhoenixFire International Coach Join Date: Sep 2006 Location: Bitch please, I'm from West Yorkshire Posts: 14,986	Cheers Neil, all's good.

05-03-2007, 10:45 AM	#5 (permalink)
PhoenixFire International Coach Join Date: Sep 2006 Location: Bitch please, I'm from West Yorkshire Posts: 14,986	So no need for Standard Form in the answer then?

05-03-2007, 10:49 AM	#6 (permalink)
Neil Pickup Cricket Web Staff Member / Global Moderator Join Date: Mar 2002 Location: Oxford, England Posts: 26,361	Depends if the question asks specifically for an answer in standard form or not!

05-03-2007, 11:38 AM	#9 (permalink)
PhoenixFire International Coach Join Date: Sep 2006 Location: Bitch please, I'm from West Yorkshire Posts: 14,986	Gah, I hated those prefixes. We had to work out how many Mega-Seconds equated to 1.98 Giga-Hours, nastily difficult.

05-03-2007, 12:00 PM	#11 (permalink)
open365 International Vice-Captain Join Date: Sep 2004 Location: liverpool Posts: 4,066	Is anyone a whiz at writing film reviews or Spanish coursework?Anyone?Please?

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