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

Tricky C1 question

Solve the equation x^2 - (6 root 3)x + 24=0, giving your answer in terms of surds, simplified as far as possible.

So I got 4root3 and 2root3 which is correct.

However then it asks:
Find all four solutions of the equation

x^4 - (6 root 3)x^2 + 24 = 0

giving your answers exactly - using indices.

Not sure how to tackle this? Any advice/explanations would be great.
Thank you!
Original post by tjthedj
Solve the equation x^2 - (6 root 3)x + 24=0, giving your answer in terms of surds, simplified as far as possible.

So I got 4root3 and 2root3 which is correct.

However then it asks:
Find all four solutions of the equation

x^4 - (6 root 3)x^2 + 24 = 0

giving your answers exactly - using indices.

Not sure how to tackle this? Any advice/explanations would be great.
Thank you!


What can you do to make your second equation to look like your first? (hint: consider a substitution)
Reply 2
Avatar for TeeEm
TeeEm
19
Original post by tjthedj
Solve the equation x^2 - (6 root 3)x + 24=0, giving your answer in terms of surds, simplified as far as possible.

So I got 4root3 and 2root3 which is correct.

However then it asks:
Find all four solutions of the equation

x^4 - (6 root 3)x^2 + 24 = 0

giving your answers exactly - using indices.

Not sure how to tackle this? Any advice/explanations would be great.
Thank you!


let x2 =y in the second equation
Original post by TeeEm
let x2 =y in the second equation



ah quadratics in disguise..

quick question, if you square root something twice, its the cubed root right?
Original post by tjthedj
ah quadratics in disguise..

quick question, if you square root something twice, its the cubed root right?


No

cube root 8, then square root 8 twice. You'll see they are not equal
Original post by tjthedj
ah quadratics in disguise..

quick question, if you square root something twice, its the cubed root right?


Nope, it's the fourth root.
Reply 6
Avatar for TeeEm
TeeEm
19
Original post by tjthedj
ah quadratics in disguise..

quick question, if you square root something twice, its the cubed root right?


fourth root

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you