What are Indicies?!

[Jenz08]

I am having some trouble understanding what indicies are.
I have looked online for a defintion, but it confuses me moreso, so could anyone please answer this question

What are indicies?!

This will help me to answer the following....
Summarise the process, explaining how 'negative indices' can be used in 'serial dilutions'?

Thanks

[angel21]

I thought indicies were corners

[squarebear]

Isn't that where you find fish? in-dee-seas.

[mollykins]

I don't know what a serial dilution is i don't think.

Are you doing a science experiment where you have to dilute something more and more? Is that what it is?

I'll start with the basics of indices.

An indice is a number to the power of another number for example five to the power of two is five square (25).

You can have any number to the power of any other number.

But when you are dealing with a number that has many zeros at the end, you do it diferently.

so say the number was 1000 you could say it was ten to the power of 100.

But if the number was 32000 you need to do it difrently.
For this you need to times a number by ten to the power somthing. in this case it would be 3.2(you always have a number les than ten followed by all digits up to where the zeros start) times 10 to the power of 3. (you don't do to the power of four ebcause the ten is already moving the number along once.)

so 3.2 x 10 to the power of 3 is 32000.

now negative indices are where the number gets smaller. to do this you would say 3.2 x 10 to the power of minus 3. this would give you an answer of 0.00032. (the times ten makes it move once and the other three make it move three more times.

[mollykins]

i hope that answers your questions about indices but i'm not sure about serial dilutions.

[Rev. Green]

mollykins: I know you meant well, but your answer has several errors, and could confuse Jenz.

10 to the power 100 is not 1000

10 to the power 3 is 1000

3.2 times 10 to the power 3 is 3200, not 32000

3.2 times 10 to the power -3 is 0.0032, not 0.00032

[rojash]

...and the singular of indices is index not indice

[rov1200]

I'm surprised your teacher did not tell you to search the internet for them

http://www.mathsrevision.net/gcse/pages.php?pa ge=26

[mollykins]

i've failed ym mock maths then.

At least i have time to revise more i'll get it right on the proper exam.

[Rev. Green]

mollykins and jenz:

Follow the link given by rov1200. That site has a good introduction to indices (ignore their spelling of "recipricol").

You won't need anything else (e.g. you'll not be asked for the square root of minus one to the power of itself! One answer is about a quarter, if you are interested.)

[Jenz08]

Thank you all for your help :)