Quick Maths Q!

oRlyYaRly

Is a repricol when ya turn the fraction upside down?

Piste

yep. or even a whole number, like the reciprocal of 2 is 1/2

Fobia

No. You invert it, multiply it by it's conjugate, then divide by it's conjugate, make sure that if you multiply THIS answer by your original number (ie before you inverted it) that you get 1. This is the reciprocal.

kittenkiller

http://encarta.msn.com/encnet/features/dictionary/DictionaryResults.aspx?refid=1861699698

I thought it was the decimal equivalent to the unit fraction. But it's not.
The inverted fraction is when you turn it upside down.
There's a page in the log tables dedicated to reciprocols as far as I can remember.

PurpleFistMixer

As far as I can recall, the reciprocal of a number is the number you multiply it with to get 1. So yeah, turn it upside down.

I remember we hadn't done it in school, and it came up on .. twas either the JC or the mock. Everyone was rather shocked.

oRlyYaRly

Thanks ya'll. Does the ABC formula start with +b or -b?

It's the one you'd use to solve x(x)+47x-5812

kittenkiller

-b +/- sqrt...

oRlyYaRly

Thanks.

And do you put the whole thing over 2a or just the part after the -b?

kittenkiller

All over 2a
http://www.themathpage.com/alg/complete-the-square.htm

oRlyYaRly

Thanks a bunch! Best go to bed now. Need to be alert to get my A.

kittenkiller

Best of luck.
It'll all come back to you when the time comes.

Ps. If you can't remember the specifics of a formula during the exam, you can always experiment for a few mins with an equation that you know the answer to to find out the little details like signs & how much goes over the 2a n stuff.

Victor

Fobia wrote:

No. You invert it, multiply it by it's conjugate, then divide by it's conjugate, make sure that if you multiply THIS answer by your original number (ie before you inverted it) that you get 1. This is the reciprocal.

Behave!

BMH

Isn't the reciprocal actually "one over"?

It just works out that it's like inverting it as if you have 6/7 and decide to find the reciprocal, you put one over it, so you get 1/6/7, which is, in simpler terms, 7/6.

might just be handy to know, in case there is a hand symbol beside it and the want to see exactly what you're doing.

PurpleFistMixer

In mathematics, the reciprocal, or multiplicative inverse, of a number x is the number which, when multiplied by x, yields 1. - Wikipedia.

Stompbox

Oh God!To put it simply,finding the reciprocal consists of turning the number upside down.No need for all this maths jargon like 'conjugate'.

JSK 252

Sweet wrote:

Oh God!To put it simply,finding the reciprocal consists of turning the number upside down.No need for all this maths jargon like 'conjugate'.

exactly. as long as you can do it who gives a crap