Date | May 2011 | Marks available | 2 | Reference code | 11M.1.sl.TZ2.5 |
Level | SL only | Paper | 1 | Time zone | TZ2 |
Command term | Find | Question number | 5 | Adapted from | N/A |
Question
The straight line L passes through the points A(−1, 4) and B(5, 8) .
Calculate the gradient of L .
Find the equation of L .
The line L also passes through the point P(8, y) . Find the value of y .
Markscheme
8−45−(−1) (M1)
Note: Award (M1) for correct substitution into the gradient formula.
23 (46, 0.667) (A1) (C2)
[2 marks]
y=23x+c (A1)(ft)
Note: Award (A1)(ft) for their gradient substituted in their equation.
y=23x+143 (A1)(ft) (C2)
Notes: Award (A1)(ft) for their correct equation. Accept any equivalent form. Accept decimal equivalents for coefficients to 3 sf.
OR
y−y1=23(x−x1) (A1)(ft)
Note: Award (A1)(ft) for their gradient substituted in the equation.
y−4=23(x+1) OR y−8=23(x−5) (A1)(ft) (C2)
Note: Award (A1)(ft) for correct equation.
[2 marks]
y=23×8+143 OR y−4=23(8+1) OR y−8=23(8−5) (M1)
Note: Award (M1) for substitution of x=8 into their equation.
y=10 (10.0) (A1)(ft) (C2)
Note: Follow through from their answer to part (b).
[2 marks]
Examiners report
Generally, a well answered question with many candidates achieving full marks. Indeed, marks which tended to be lost were as a result of premature rounding rather than method. On a number of scripts, part (a) produced a rather curious wrong answer of 8.2 following a correct gradient expression. It would seem that this was as a result of typing into the calculator 8−4÷5+1.
Generally, a well answered question with many candidates achieving full marks. Indeed, marks which tended to be lost were as a result of premature rounding rather than method.
Generally, a well answered question with many candidates achieving full marks. Indeed, marks which tended to be lost were as a result of premature rounding rather than method.