Maths help

[Krowdon]

Guys I don't get math. Can someone explain to me how to solve this? Practice SATs.

http://i.imgur.com/hunaE.jpg

[Ashyra Nightwing]

what do the brackets mean


edit: i am terrible at maths and i plan to work this out as a sort of challenge for myself

[Krowdon]

That's the function of x. I guess they want to keep the f and x seperate.

[Ashyra Nightwing]

.... I have no idea what that means



This is, I assume, why I haven't become a ~~~~rwl master~~~~ even though I've been playing for a literal decade


[fake edit: while looking for "~" on the flapple mac keyboard I noticed it is gone and in its place is "§". Does "§" actually have a purpose?]

[Krowdon]

§ looks like a hurricane

[Ashyra Nightwing]

it's ungoogleable too. ± and §, what are you

[Krowdon]

The first one is a positive negative sign!

So if x was equal to both positive and negative 3, you could write x= ±3

[Ashyra Nightwing]

but how could that be so? or is this in some kind of hypothetical maths universe?

[Krowdon]

We used it in class last year.

[Shadow]

You have 2 unknowns - k and a. So you need two equations to solve for them. You are actually given three equations in the table, (dunno why you are given three, but whatever).

You know that f(-1)=1/8, or written out in full:

ka^(-1)=1/8

You know that f(0)=1/2, or

ka^0=1/2

but a^0=1 (anything^0=1), so k=1/2

plug this back into the first equation:

1/2 * a^-1 = 1/8

a^-1=1/4

a=4

I guess you can use the third equation they given you to verify that k=1/2 and a=4 works:

f(1) = 2 = ka^1 = 1/2*4 = 2

Success!

[Shadow]

By the way, you use  ±3 to express possible answers to equations in compact form. For example, if I tell you that x^2=9, then the solution to this is  x= ±3 because (-3)^2=3^2=9

[Ashyra Nightwing]

I get it now :P It would still take a while for me to figure out but at least I know what's going on. And I know what 'function' means now, haha. I haven't done any maths whatsoever since the age of 16, unless you count Professor Layton puzzles and sudoku

[Krowdon]

Thank you shadow! I'll have to try that myself in a little while because I have to go shopping. :/

[Camaclue]

SHOP! SHOP TILL YOU HAVE BOUGHT WHAT YOU NEEDED!

[Krowdon]

I dont need anything. I'm just being dragged along.

If everyone else went, I'd be here having solo Karaoke night. Full volume music. Probably ABBA and some musicals. But no. I have to go too. -__-