Finding the new equation (1 Viewer)

[ronnknee]

eg. x^3 + 5x^2 + 11 = 0
Find the polynomial equation whose roots are a^2, b^2, c^2

I know how to do it but I have a few questions about presenting the answer.
The answer to this question is x^3 - 25x^2 - 110x - 121 = 0

Would it be marked incorrect if I use a variable different from x?
eg. y^3 - 25y^2 - 110y - 121 = 0

Would it be marked incorrect if it isn't in simplest form?
eg. 2y^3 - 50y^2 - 220y - 242 = 0

 

[Sandchairs]

at my school.
1. it doesnt matter what variable u use as long as u define it ie. y=a^2
2. you will lose only 1 mark for your example (2y^3 - 50y^2 - 220y - 242 = 0) cause its obvious you could divide by 2

 

[Slidey]

You might lose a mark if you don't divide by 2. It depends on how your marker is feeling.

Generally a good marker won't deduct markers unless a genuine mistake has been made - in this case, no mistake has been made, and you followed the steps required to solve the problem.

I mean, you could argue the point anyway, because it says "find the polynomial equation blah blah". There's actually an infinite number of such equations, all scalar multiples of each-other (vector spaces and such), thus any one of them could technically be correct.

 

[undalay]

If they don't state monic, or something, then it should be fine

 

[conics2008]

if y=x^n+.........+c where c=constant

Find the new equation with roots ab,by,ay

YOU MUST !

Represent it in y=x^n+.......+c form not x=y^n+.............+c this would give you a different function. ^^ this is function of x and the othr one is function f y. Two different things.... why dont you keep the maths simple, and stick to x.

Because you should write it like this x=aby/y and what ever aby=? put it there

ten x=?/y >> xy=? therefor y=?/x which is you're root. then sub tht into f(x).

I hope this helped. =0

 

[undalay]

if y=x^n+.........+c where c=constant

Find the new equation with roots ab,by,ay

YOU MUST !

Represent it in y=x^n+.......+c form not x=y^n+.............+c this would give you a different function. ^^ this is function of x and the othr one is function f y. Two different things.... why dont you keep the maths simple, and stick to x.

Because you should write it like this x=aby/y and what ever aby=? put it there

ten x=?/y >> xy=? therefor y=?/x which is you're root. then sub tht into f(x).

I hope this helped. =0

u make no sense bro

 

[ice ken]

u make no sense bro

lol he talks bs

 

[nottellingu]

I lost 1 mark out of 3 for not simplifing the eqn for one of those forming eqn q's and it wasnt obvious it was divisivble by 7 or something and had massive no.'s. Always simplify in any q or be prepared to take the risk of loosing marks esp in ext 2.

 

[ronnknee]

if y=x^n+.........+c where c=constant

Find the new equation with roots ab,by,ay

YOU MUST !

Represent it in y=x^n+.......+c form not x=y^n+.............+c this would give you a different function. ^^ this is function of x and the othr one is function f y. Two different things.... why dont you keep the maths simple, and stick to x.

Because you should write it like this x=aby/y and what ever aby=? put it there

ten x=?/y >> xy=? therefor y=?/x which is you're root. then sub tht into f(x).

I hope this helped. =0

But we're trying to find a new equation where all the variables are consistent, and not a function though?

 

[conics2008]

--------------------------------------------------------------------------------eg. x^3 + 5x^2 + 11 = 0Find the polynomial equation whose roots are a^2, b^2, c^2I know how to do it but I have a few questions about presenting the answer.The answer to this question is x^3 - 25x^2 - 110x - 121 = 0Would it be marked incorrect if I use a variable different from x?eg. y^3 - 25y^2 - 110y - 121 = 0Would it be marked incorrect if it isn't in simplest form?eg. 2y^3 - 50y^2 - 220y - 242 = 0LoL I know i didn't make any sense but I undrstood what he said.. sorry im bad at explainin.. i hav to explain to my teacher aswell =)The guy said the poly x^3+5x^2+11=0 find the new poly with roots a^2 where is alpha^2.... I told him no you cant represent you're answer in f(y)=y^n+.....+c where c = constant...He has to put it in the form of f(x) not f(y)The answer should be like this a^2=x therefore a=x^1/2 sub a= x^1/2 into f(x)(x^1/2)^3 + 5(x^1/2)^2 + 11 = = x^3/2 +5x +11 = 0 =(x^3/2)^2= ( -5x-11)^2=x^3= 25x^2+110x+121 therefore the new poly becomes f(x)=x^3-25x^2 - 110x-121 because the orginal equation has roots at x NOT Y therefore the new poly must have roots at X not Y.. thats why you cant use f(x)and to the fag who said i was talking shit, go study 4units before you talk, you didn't even understand shit.. cuz you're an idiot.. faggot
EDIT: wtff is wrong with this.. i set it out and look how it turned out.. =(

 

[Slidey]

Conics2008, I think you're probably fundamentally a nice guy who means well, but please calm down, stop insulting other users, and tone your ego down a bit.

 

[A High Way Man]

ahaha, conics2008 went insane in the MAINFRAME
COMPUTER EXPLODE 10101010101!!

 

[tacogym27101990]

u need to fucking chill conics
its just maths...

 

[conics2008]

lol.. im calm, I dont take crap from people saying shit =) lol..


I'm cool =)

hey why did my post turn out like that.. I made it go down the page with 1 line in between.. =)

sorry if I insulted anyone =) Peace