05 Jun '06 08:30

Work this out:

(y+4)(y-7)(y+6)= (?)

and if you are really smart, factorise:

y3 - 54= (?)

(y+4)(y-7)(y+6)= (?)

and if you are really smart, factorise:

y3 - 54= (?)

- Joined
- 02 Jun '06
- Moves
- 2420

Palmerston North- Joined
- 28 Nov '05
- Moves
- 24334

- Joined
- 23 Aug '04
- Moves
- 24791

tinyurl.com/y9ls7wbl- Joined
- 06 Sep '04
- Moves
- 25076

p^2.sin(phi)- Joined
- 12 Mar '03
- Moves
- 37204

- Joined
- 09 Apr '06
- Moves
- 27526

B is for bye bye- Joined
- 02 Jun '06
- Moves
- 2420

Palmerston North- Joined
- 02 Jun '06
- Moves
- 2420

Palmerston North- Joined
- 02 Jun '06
- Moves
- 2420

Palmerston North- Joined
- 06 Sep '04
- Moves
- 25076

p^2.sin(phi)06 Jun '06 06:00

I do get homework. But I do it myself and even if I were to ask for help here I doubt most of you could manage to say anything useful.*Originally posted by Knight Square***XanthosNZ is a kiwi just like me and us NZders do get Homework right?**

Also, AThousandYoung is right. Hope you fail.- Joined
- 02 Jun '06
- Moves
- 2420

Palmerston North06 Jun '06 09:37

What, you think this was my homework, now. XanthousNZ that is just for fun. And I am only 4th Form and this is 6th Form Maths, Level 2 XanthousNZ Level2.*Originally posted by XanthosNZ***I do get homework. But I do it myself and even if I were to ask for help here I doubt most of you could manage to say anything useful.**

Also, AThousandYoung is right. Hope you fail.- Joined
- 23 Aug '04
- Moves
- 24791

tinyurl.com/y9ls7wbl- Joined
- 14 Feb '04
- Moves
- 28719

False berry08 Jun '06 14:59

One interesting pattern to note that may be helpful for quick calculations in the future:*Originally posted by Knight Square***Work this out:**

(y+4)(y-7)(y+6)= (?)

and if you are really smart, factorise:

y3 - 54= (?)

(x+A)(x+B) = x^2 + (A+B)x + AB

(x+A)(x+B)(x+C) = x^3 + (A+B+C)x^2 + (AB+AC+AB)x + ABC

(x+A)(x+B)(x+C)(x+D) = x^4 + (A+B+C+D)x^3 + (AB+AC+AD+BC+BD+CD)x^2 + (ABC+ABD+ACD+BCD)x + ABCD

etc...

This pattern arises from the combinatoric process of selecting "n" x's and "m-n" constants from the factorization of a polynomial of degree "m". It's handy to remember, because it saves you making mechanical errors keeping track of all the x^2 and such.- Joined
- 28 Mar '06
- Moves
- 9908

Voice of Reason08 Jun '06 15:511 edit

If you want a quick estimate of Y3-54=?*Originally posted by Knight Square***Work this out:**

(y+4)(y-7)(y+6)= (?)

and if you are really smart, factorise:

y3 - 54= (?)

just take the square root of 54 and divide by 2. The answer is usually accurate to 1 or 2 decimal places with small numbers like 54....3.67 in this case

EDIT: welcome back PB6- Joined
- 14 Feb '04
- Moves
- 28719

False berry08 Jun '06 16:04

Good to be back! But I'm still going to lurk for a while. I just hate people in general, so I'm ramping up to full-blown posting.*Originally posted by uzless***If you want a quick estimate of Y3-54=?**

just take the square root of 54 and divide by 2. The answer is usually accurate to 1 or 2 decimal places with small numbers like 54....3.67 in this case

EDIT: welcome back PB6