Date | May 2014 | Marks available | 6 | Reference code | 14M.1.hl.TZ2.4 |
Level | HL only | Paper | 1 | Time zone | TZ2 |
Command term | Find | Question number | 4 | Adapted from | N/A |
Question
The roots of a quadratic equation 2x2+4x−1=0 are α and β.
Without solving the equation,
(a) find the value of α2+β2;
(b) find a quadratic equation with roots α2 and β2.
Markscheme
(a) using the formulae for the sum and product of roots:
α+β=−2 A1
αβ=−12 A1
α2+β2=(α+β)2−2αβ M1
=(−2)2−2(−12)
=5 A1
Note: Award M0 for attempt to solve quadratic equation.
[4 marks]
(b) (x−α2)(x−β2)=x2−(α2+β2)x+α2β2 M1
x2−5x+(−12)2=0 A1
x2−5x+14=0
Note: Final answer must be an equation. Accept alternative correct forms.
[2 marks]
Total [6 marks]
Examiners report
[N/A]