Math Is Fun Forum

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Proportionality

y is directly proportional to x² .
When x = 2, y = 36
(by the way, I don't know how to do a proportional sign?)

a) Express y in terms of x.

z is inversely proportional to x.
When x=3, z =2
b) Show that z = c y^n, where c and n are numbers and c > 0. (You must find the values of c and n)

This is the furthest I get:

And I kind of run out there. Can anyone help?

Thanks.

Last edited by Daniel123 (2007-06-02 03:01:24)

Big Mac

Member

Registered: 2007-05-19

Posts: 20

Re: Proportionality

Thats the right answer I reckon Danial because

is exactly the same as [maths]18 y^-0.5[/math]

In your solution you said x is divided by 2 but the changed it to a 3, be careful.

Good luck on Monday.

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I think, therefore I am.

Big Mac

Member

Registered: 2007-05-19

Posts: 20

Re: Proportionality

Oop, trying to be clever with computer commands. Will have another go - hope you understand what I meananyway.
Ans:

---

I think, therefore I am.

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Re: Proportionality

Oops didn't notice that... I've changed it now. Thanksss :D:D

Big Mac

Member

Registered: 2007-05-19

Posts: 20

Re: Proportionality

Hey Daniel - my computers crashed at home so wont be on again until Monday afternoon. Just wishing you all the best in your maths exam mon morn. You'll be fine. Lets know what you thought of it anyway. Cheers.

---

I think, therefore I am.

Identity

Member

Registered: 2007-04-18

Posts: 934

Re: Proportionality

Daniel, you can use this site as a reference when using LateX
http://www.maths.tcd.ie/~dwilkins/LaTeXPrimer/

E.g

is \propto

Daniel123

Member

Registered: 2007-05-23

Posts: 663

Re: Proportionality

Thanks Identity.