Date | May 2018 | Marks available | 3 | Reference code | 18M.1.hl.TZ2.2 |
Level | HL only | Paper | 1 | Time zone | TZ2 |
Command term | Sketch | Question number | 2 | Adapted from | N/A |
Question
Sketch the graphs of y=x2+1 and y=|x−2| on the following axes.
Solve the equation x2+1=|x−2|.
Markscheme
straight line graph with correct axis intercepts A1
modulus graph: V shape in upper half plane A1
modulus graph having correct vertex and y-intercept A1
[3 marks]
METHOD 1
attempt to solve x2+1=x−2 (M1)
x=6 A1
Note: Accept x=6 using the graph.
attempt to solve (algebraically) x2+1=2−x M1
x=23 A1
[4 marks]
METHOD 2
(x2+1)2=(x−2)2 M1
x24+x+1=x2−4x+4
0=3x24−5x+3
3x2−20x+12=0
attempt to factorise (or equivalent) M1
(3x−2)(x−6)=0
x=23 A1
x=6 A1
[4 marks]