Date | May 2018 | Marks available | 6 | Reference code | 18M.2.hl.TZ1.2 |
Level | HL only | Paper | 2 | Time zone | TZ1 |
Command term | Find | Question number | 2 | Adapted from | N/A |
Question
The equation x2−5x−7=0 has roots α and β. The equation x2+px+q=0 has roots α+1 and β+1. Find the value of p and the value of q.
Markscheme
METHOD 1
α+β=5,αβ=−7 (M1)(A1)
Note: Award M1A0 if only one equation obtained.
(α+1)+(β+1)=5+2=7 A1
(α+1)(β+1)=αβ+(α+β)+1 (M1)
=−7+5+1=−1
p=−7,q=−1 A1A1
METHOD 2
α=5+√532=6.1…;β=5−√532=−1.1… (M1)(A1)
α+1=7+√532=7.1…;β+1=7−√532=−0.1… A1
(x−7.14…)(x+0.14…)=x2−7x−1 (M1)
p=−7,q=−1 A1A1
Note: Exact answers only.
[6 marks]
Examiners report
[N/A]