Harder 2U Qs : Quadratic Polynomial (1 Viewer)

[Tsylana]

Well i stumbled across this question and im not sure if i'm doing it right or not because i keep getting really strange answers.... ><"

The question goes Find the relationship between a and b in the equation ax^2 + bx + c = 0 ; When the larger root exceeds the smaller root by 1.

><"

Thanks guys =].

 

[lyounamu]

Well i stumbled across this question and im not sure if i'm doing it right or not because i keep getting really strange answers.... ><"

The question goes Find the relationship between a and b in the equation ax^2 + bx + c = 0 ; When the larger root exceeds the smaller root by 1.

><"

Thanks guys =].

Let the roots be @ and @+1.

@ + @+1 = -b/a
2@ + 1 = -b/a
-2a@ - a = b
b= -2a@ - a

Like this?

 

[Tsylana]

errr o__O". ok lol. now i feel like a dumbass... ><"

would i need to find the alpha term and sub it into that equation?

 

[lyounamu]

errr o__O". ok lol. now i feel like a dumbass... ><"

would i need to find the alpha term and sub it into that equation?

No. Alpha is one of the roots that is unknown. Alpha can be anything.

 

[Tsylana]

hmmm but if

2alpha + 1 = -b/a

then can't you do this


alpha =(-b/a - 1)/2

and sub it into that equation you just wrote?

 

[lyounamu]

hmmm but if

2alpha + 1 = -b/a

then can't you do this


alpha =(-b/a - 1)/2

and sub it into that equation you just wrote?

If you do that, you will get b = b. That way, you don't show the relationship between a & b.

 

[Tsylana]

hmm something just doesn't seem right with this question ><"

the follow on questions "The roots are in ratio of 2:3" and it asks the same thing... ><" it seems too easy to be considerred "Harder 2U Qs" but oh well... this is like damaging my brain haha ><" makes me feel so stupid and smart and the same time -.-"

 

[foram]

hmm something just doesn't seem right with this question ><"

the follow on questions "The roots are in ratio of 2:3" and it asks the same thing... ><" it seems too easy to be considerred "Harder 2U Qs" but oh well... this is like damaging my brain haha ><" makes me feel so stupid and smart and the same time -.-"

Harder 2U isn't supposed to be very hard.

 

[tommykins]

ax^2 + bx + c = 0

Roots are 2@:3@

5@ = -b/a

a5@ = -b
b = -a5@