DeadlyKamina
New member
- Joined
- Apr 1, 2016
- Messages
- 8
Hi, I'm really not sure if this is the right place but if it's not I'm happy to reupload somewhere else.
I never got taught this mainly because its A level work and I'm still a GCSE student but I have a massive passion of maths but I digress.
So it concerns 'Roots and Coefficients of Quadratic Equations' (I wanna get a headstart and I'm really enjoying it I just need a nudge in the right direction)
Alpha will be called 'E' and Beta will be called 'F' for ease of use and also 'a' and 'b' are taken up by the quadratic.
For the equation Ax2+Bx+C with roots E and F
The sum of roots = E+F= -B/A
The product of roots = EF= C/A
I must find the quadratic whose roots are E + 5/F and F + E/5 where E and F are the roots of 2x2+7x-3=0
So I correctly worked out the sum of the roots, (E + 5/F) + (F + E/5) which is (E+F) + 5(E+F)/EF
Then I took the rules using the quadratic to sub in, so I swapped all E+F for -B/A, so -7/2 and subbed all EF for C/A which is -3/2.
Hence -7/2 + (5(-7/2))/(-3/2)
Long story short, 49/6, thats cool that's what the answer says.
MY ISSUE:
Doing the product I get (E + 5/F)(F + 5/E) I get this is EF+(5E/E)+(5F/F)+(25/EF)
Which I get as EF + 4E + 4F + 25/EF
Now the answer says I SHOULD get EF + 25/EF + 10
WHERE DOES THE + 10 COME FROM?!?!?
I never got taught this mainly because its A level work and I'm still a GCSE student but I have a massive passion of maths but I digress.
So it concerns 'Roots and Coefficients of Quadratic Equations' (I wanna get a headstart and I'm really enjoying it I just need a nudge in the right direction)
Alpha will be called 'E' and Beta will be called 'F' for ease of use and also 'a' and 'b' are taken up by the quadratic.
For the equation Ax2+Bx+C with roots E and F
The sum of roots = E+F= -B/A
The product of roots = EF= C/A
I must find the quadratic whose roots are E + 5/F and F + E/5 where E and F are the roots of 2x2+7x-3=0
So I correctly worked out the sum of the roots, (E + 5/F) + (F + E/5) which is (E+F) + 5(E+F)/EF
Then I took the rules using the quadratic to sub in, so I swapped all E+F for -B/A, so -7/2 and subbed all EF for C/A which is -3/2.
Hence -7/2 + (5(-7/2))/(-3/2)
Long story short, 49/6, thats cool that's what the answer says.
MY ISSUE:
Doing the product I get (E + 5/F)(F + 5/E) I get this is EF+(5E/E)+(5F/F)+(25/EF)
Which I get as EF + 4E + 4F + 25/EF
Now the answer says I SHOULD get EF + 25/EF + 10
WHERE DOES THE + 10 COME FROM?!?!?