Date | November 2019 | Marks available | 2 | Reference code | 19N.2.SL.TZ0.T_2 |
Level | Standard Level | Paper | Paper 2 | Time zone | Time zone 0 |
Command term | Find | Question number | T_2 | Adapted from | N/A |
Question
The diagram shows the straight line L1. Points A(-9, -1), M(-3, 2) and C are points on L1.
M is the midpoint of AC.
Line L2 is perpendicular to L1 and passes through point M.
The point N(k, 4) is on L2.
Find the gradient of L1.
Find the coordinates of point C.
Find the equation of L2. Give your answer in the form ax+by+d=0, where a, b, d∈ℤ.
Find the value of k.
Find the distance between points M and N.
Given that the length of AM is √45, find the area of triangle ANC.
Markscheme
2-(-1)-3-(-9) (M1)
Note: Award (M1) for correct substitution into the gradient formula.
=12 (36, 0.5) (A1)(G2)
[2 marks]
-3=-9+x2 (-6+9=x) and 2=-1+y2 (4+1=y) (M1)
Note: Award (M1) for correct substitution into the midpoint formula for both coordinates.
OR
(M1)
Note: Award (M1) for a sketch showing the horizontal displacement from M to C is 6 and the vertical displacement is 3 and the coordinates at M.
OR
-3+6=3 and 2+3=5 (M1)
Note: Award (M1) for correct equations seen.
(3, 5) (A1)(G1)(G1)
Note: Accept x=3, y=5. Award at most (M1)(A0) or (G1)(G0) if parentheses are missing.
[2 marks]
gradient of the normal =-2 (A1)(ft)
Note: Follow through from their gradient from part (a).
y-2=-2(x+3) OR 2=-2(-3)+c (M1)
Note: Award (M1) for correct substitution of M and their gradient of normal into straight line formula.
2x+y+4=0 (accept integer multiples) (A1)(ft)(G3)
[3 marks]
2(k)+4+4=0 (M1)
Note: Award (M1) for substitution of y=4 into their equation of normal line or substitution of M and (k, 4) into equation of gradient of normal.
k=-4 (A1)(ft)(G2)
Note: Follow through from part (c).
[2 marks]
√(-4+3)2+(4-2)2 (M1)
Note: Award (M1) for correctly substituting point M and their N into distance formula.
√5 (2.24, 2.23606…) (A1)(ft)
Note: Follow through from part (d).
[2 marks]
12×(2×√45)×√5 (M1)
Note: Award (M1) for their correct substitution into area of a triangle formula. Award (M0) for their 12×(√45)×√5 without any evidence of multiplication by 2 to find length AC. Accept any other correct method to find the area.
15 (A1)(ft)(G2)
Note: Accept 15.02637… from use of a 3 sf value for √5. Follow through from part (e).
[2 marks]