I did this in November/December I think, I haven't been able to do d yet but I just got e and it's correct according to the book.
What have you tried so far?

Reply 6

S2M

@RDKGames @ghostwalker

Reply 7

Imstudying...

Original post by ralph9694

I did this in November/December I think, I haven't been able to do d yet but I just got e and it's correct according to the book.
What have you tried so far?

I got to (-3/4)^2- 6(4/3) but I got terms afterwards to get to the answer for the question that I can’t factorise. Can u show me method for e? I can’t work it out

(edited 6 years ago)

Reply 8

ralph9694

for e I started out expanding

(\alpha\beta\gamma + \alpha\beta\delta + \alpha\gamma\delta + \beta\gamma\delta)^2

and the comparing that to what is in the question

Reply 9

Imstudying...

Original post by ralph9694

for e I started out expanding

(\alpha\beta\gamma + \alpha\beta\delta + \alpha\gamma\delta + \beta\gamma\delta)^2

and the comparing that to what is in the question

Thanks I’ll try that out. Have u got anywhere with d?

Reply 10

ralph9694

I'm trying a similar thing, expanding another squared bracket, 6 terms in each, so it's taking a while.

Reply 11

blockingHD

Original post by ralph9694

for e I started out expanding

(\alpha\beta\gamma + \alpha\beta\delta + \alpha\gamma\delta + \beta\gamma\delta)^2

and the comparing that to what is in the question

And do the same for

(\sum \alpha\beta)^{2}

Reply 12

Imstudying...

Original post by blockingHD

And do the same for (\sum_\alpha\beta)^{2}[\latex]

That’s the bit where I am stuck. I worked all that out but I can’t factorise them into the values I know. Not all the algebra have the same letter.

(edited 6 years ago)

Reply 13

ralph9694

with part e, after expanding the brackets, ignoring the

(\alpha\beta\gamma)^2

terms, try taking out a common factor (one should jump out) of everything left over

(edited 6 years ago)

Reply 14

Imstudying...

Original post by ralph9694

with part e, after expanding the brackets, ignoring the

(\alpha\beta\gamma)^2

terms, try taking out a common factor (one should jump out) of everything left over

Thanks I ve got the right answer for e now

Reply 15

ralph9694

I just got it for d using the same method

Reply 16

Imstudying...

Original post by ralph9694

I just got it for d using the same method

What is the common factor? I can’t seem to find it

Reply 17

ralph9694

I think for d it's a bit harder, I initially saw the

\alpha\beta\gamma\delta

and put it aside as we are told what it's value is, but I realised it was useful to add 2 more of it if that makes sense, and then factorise from there.

Reply 18

Notnek

Original post by Janej77

I am struggling with 8d and e. Can someone help plz?

For d, If you've covered the substitution method a much less tedious method for this question is to first write out the quartic polynomial in the form

x^4 + bx^3 + cx^2 + dx + e

Then find the polynomial with roots

\alpha^2, \beta^2, \gamma^2

and

\delta^2

by using substitution.

You'll only need to find the coefficient of

x^3

in this polynomial since this will be equal to

-\sum \alpha^2\beta^2

which is what you need.

And part e can be done in a similar way.

If you've covered the substitution method and want more help with this then let me know.