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Reply 1
if the roots are equal, then b^2 - 4ac = 0
8^2 - (4*2)(k + 3) = 0
64 - 8k + 24 = 0
88 = 8k
k = 11
Reply 2
thanks for the help, do you know of any websites that are good for this type of maths (discriminant etc)?
Reply 3
greenie787
thanks for the help, do you know of any websites that are good for this type of maths (discriminant etc)?

nope, fraid not. dont you have a p1 textbook?
Reply 4
yeah but i'm finding it hard to understand, i get most of the stuff its just this and comparing coeficients
Reply 5
edders
if the roots are equal, then b^2 - 4ac = 0
8^2 - (4*2)(k + 3) = 0
64 - 8k + 24 = 0
88 = 8k
k = 11




This may be wrong. I think you should check it. I get k=5.
Reply 6
greenie787
yes i just checked the mark scheme and it is 5. can you write up how you did it please?




2x^2 + 8x + (k+3) = 0

b^2 - 4ac = 0 (equal roots)
8^2 - 4.2(k + 3) = 0
64 - 8(k + 3) = 0
64 - 8k - 24 = 0
8k = 40
k = 5.
Reply 7
thank you
Reply 8
Ralfskini
2x^2 + 8x + (k+3) = 0

b^2 - 4ac = 0 (equal roots)
8^2 - 4.2(k + 3) = 0
64 - 8(k + 3) = 0
64 - 8k - 24 = 0
8k = 40
k = 5.

Yep I can confirm that is correct, k=5
Reply 9
what about when the roots are >0 or < 0, is it possible to solve then?

also there is a similar question worth 1 mark asking with a reason to "state the number of real roots of"
x^3 -3x^2+6=0
Reply 10
Ralfskini
2x^2 + 8x + (k+3) = 0

b^2 - 4ac = 0 (equal roots)
8^2 - 4.2(k + 3) = 0
64 - 8(k + 3) = 0
64 - 8k - 24 = 0
8k = 40
k = 5.

yes very clever. it was only a small mistake with the signs.
edders
yes very clever. it was only a small mistake with the signs.




Forgiven. :wink:
Reply 12
greenie787
what about when the roots are >0 or < 0, is it possible to solve then?

also there is a similar question worth 1 mark asking with a reason to "state the number of real roots of"
x^3 -3x^2+6=0

>0 means two real different roots.
<0 means no real roots. you can solve it using complex numbers though, but thats beyond alevel.
Reply 13
edders
yes very clever. it was only a small mistake with the signs.

Edders do Unis look favourably on you doing a gap year?
Reply 14
2776
Edders do Unis look favourably on you doing a gap year?

i dont think they care either way, tbh
Reply 15
edders
i dont think they care either way, tbh

Hmm, ans you arn't bothered about the extra tutition fees that you will be paying?
Reply 16
2776
Hmm, ans you arn't bothered about the extra tutition fees that you will be paying?

im not paying extra tuition fees. im going in 2004.
Reply 17
edders
im not paying extra tuition fees. im going in 2004.

Yes, and tution fees are in place by 3006 arn't they? So in 2006 you will be paying an extra year of tuition fee.
Reply 18
2776
Yes, and tution fees are in place by 3006 arn't they? So in 2006 you will be paying an extra year of tuition fee.

for people starting 2006, i believe. :confused:
Reply 19
edders
for people starting 2006, i believe. :confused:

lol, yes sorry.

But arn't teh fees start for 2006 for all people including those who study then as well? So you would pay an extra years of tutition fees if you havnt taken a gap year...

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