The Student Room Group
Uni students - Complete our survey >>
Uni students - Complete our survey >>
Uni students - Complete our survey >>

Maths Help

Can anyone just give me a little advice on how to start this? I should be okay from there...

h(x)=2x^2+(k+4)x+k, where k is a real constant.
Find the discriminant of h(x) in terms of k
Original post by _Yasemin_
Can anyone just give me a little advice on how to start this? I should be okay from there...

h(x)=2x^2+(k+4)x+k, where k is a real constant.
Find the discriminant of h(x) in terms of k


It's asking for the discriminant, which I'd assume you know as b2−4acb^2-4ac.

Can you identify what a,b,ca,b,c are from the quadratic you're given?
Reply 2
Avatar for _Yasemin_
_Yasemin_
OP
12
Original post by RDKGames
It's asking for the discriminant, which I'd assume you know as b2−4acb^2-4ac.

Can you identify what a,b,ca,b,c are from the quadratic you're given?


Yeah, I believe a would be 2, b would be (k+4) and c would be k, but my issue is doesn't it usually say that it has two equal roots or something like that? Because then you know whether it is b^2-4ac=0, b^2-4ac>0 or b^2-4ac<0? Or is this not necessary at this stage?
Original post by _Yasemin_
Yeah, I believe a would be 2, b would be (k+4) and c would be k, but my issue is doesn't it usually say that it has two equal roots or something like that? Because then you know whether it is b^2-4ac=0, b^2-4ac>0 or b^2-4ac<0? Or is this not necessary at this stage?


Not necessary at this stage. All the question wants is the discriminant.
Reply 4
Avatar for _Yasemin_
_Yasemin_
OP
12
Original post by RDKGames
Not necessary at this stage. All the question wants is the discriminant.


Okay, thanks for clearing that up.

So, .

(k+4)^2-(4*2*k) = 0
k^2+8k+16-8k = 0
k^2+16 = 0

But then this gives me a math error as I can't find the square root of a negative number? Must have gone wrong somewhere..
Original post by _Yasemin_
Okay, thanks for clearing that up.

So, .

(k+4)^2-(4*2*k) = 0
k^2+8k+16-8k = 0
k^2+16 = 0

But then this gives me a math error as I can't find the square root of a negative number? Must have gone wrong somewhere..


Why have you put the discriminant equal to 0?
Original post by _Yasemin_
Okay, thanks for clearing that up.

So, .

(k+4)^2-(4*2*k) = 0
k^2+8k+16-8k = 0
k^2+16 = 0

But then this gives me a math error as I can't find the square root of a negative number? Must have gone wrong somewhere..


No need to put it =0 and solve it. You are thinking about roots again for some reason.
Reply 7
Avatar for _Yasemin_
_Yasemin_
OP
12
Ahh because I had a whole worksheet on roots and this randomly on the end, it's confusing my brain.
I don't really want you to tell me the answer or how to work it out directly, but perhaps you could let me know the form the answer would be in? Then perhaps I could figure out how to get it on my own?
Original post by _Yasemin_
Ahh because I had a whole worksheet on roots and this randomly on the end, it's confusing my brain.
I don't really want you to tell me the answer or how to work it out directly, but perhaps you could let me know the form the answer would be in? Then perhaps I could figure out how to get it on my own?


What are you on about?? You have done the question but decided to put =0 and try to solve it.

The answer is k2+16k^2 + 16.

Move onto the next question.
Reply 9
Avatar for _Yasemin_
_Yasemin_
OP
12
Original post by RDKGames
What are you on about?? You have done the question but decided to put =0 and try to solve it.

The answer is k2+16k^2 + 16.

Move onto the next question.


That's it? Why do I always over complicate things, thank you so much

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you