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school. “Paper 42” means Paper 4, variant 2.
Practice questions
Original questions written by HomiLabs in the style of the exam, with answers and mark schemes. They are not
Cambridge past paper questions and have not been reviewed by Cambridge. Try each one before opening the answer.
Q1Distances (point, plane, skew lines) · Core · Paper 1 style · 5 marks
(a)Find the perpendicular distance from the point P(3, −1, 4) to the plane Π with equation 2x − 2y + z = 5.[2]
(b)Find the coordinates of the foot of the perpendicular from P to Π.[3]
Show answer
(a) 7/3
M1: |2(3) − 2(−1) + 4 − 5| / √(4 + 4 + 1)A1: 7/3
(b) (13/9, 5/9, 29/9)
M1: point on the normal through P: (3 + 2t, −1 − 2t, 4 + t)M1: substitute into Π: 9t + 7 = 0, so t = −7/9A1: foot = (13/9, 5/9, 29/9)
Q2Distances (point, plane, skew lines) · Core · Paper 1 style · 4 marks
(a)Show that the planes Π₁: x + 2y − 2z = 4 and Π₂: −2x − 4y + 4z = 22 are parallel.[1]
(b)Find the distance between Π₁ and Π₂.[3]
Show answer
(a) The normal of Π₂ is −2 times the normal of Π₁, so the normals are parallel and so are the planes.
B1: normal of Π₂ = −2(i + 2j − 2k)
(b) 5
M1: write Π₂ as x + 2y − 2z = −11M1: distances from origin 4/3 and −11/3 (same unit normal, opposite sides)A1: (4 − (−11))/3 = 5
Q3Distances (point, plane, skew lines) · Core · Paper 1 style · 4 marks
(a)The plane Π has equation r · (6i + 2j − 3k) = 14. Find the perpendicular distance of Π from the origin.[1]
(b)Find the perpendicular distance from the point A(1, 4, −2) to Π, and state whether A is on the same side of Π as the origin.[3]
Show answer
(a) 2
B1: |n| = √(36 + 4 + 9) = 7, distance 14/7 = 2
(b) 6/7; A and the origin are on opposite sides of Π
M1: |6(1) + 2(4) − 3(−2) − 14| / 7A1: 6/7B1: r·n = 20 at A (> 14) but 0 at O (< 14), so A and O are on opposite sides
Q4Distances (point, plane, skew lines) · Standard · Paper 1 style · 5 marks
(a)The lines l₁ and l₂ have equationsl₁: r = i + 2j − k + λ(2i + j + 3k)l₂: r = 4i − j + 2k + μ(i − 2j + k)Find a vector that is perpendicular to both l₁ and l₂.[2]
(b)Find the shortest distance between l₁ and l₂, giving your answer in exact form.[3]
Show answer
(a) 7i + j − 5k (or any multiple)
M1: cross product of the directions (2, 1, 3) × (1, −2, 1)A1: (7, 1, −5)
Q5Distances (point, plane, skew lines) · Standard · Paper 1 style · 6 marks
(a)The line l has equation r = i + 2k + t(2i + j − 2k) and the point P has coordinates (5, 1, −2).Find the coordinates of the point N on l such that PN is perpendicular to l.[4]
(b)Hence find the perpendicular distance from P to l.[2]
Q6Distances (point, plane, skew lines) · Standard · Paper 1 style · 6 marks
(a)The points A, B and C have coordinates A(1, 2, 0), B(3, −1, 2) and C(0, 4, 1). Find an equation of the plane ABC in the form ax + by + cz = d.[4]
(b)The point D has coordinates (6, 5, −3). Find the perpendicular distance from D to the plane ABC.[2]
Show answer
(a) 7x + 4y − z = 15
M1: AB = (2, −3, 2), AC = (−1, 2, 1)M1: AB × ACA1: normal (7, 4, −1) (or multiple)A1: 7x + 4y − z = 15
(b) 25√66/33 ≈ 6.15
M1: |7(6) + 4(5) − (−3) − 15| / √66A1: 50/√66
Q7Distances (point, plane, skew lines) · Standard · Paper 1 style · 5 marks
(a)The line l has equation r = i + 2j + 3k + t(i − j + 2k) and the plane Π has equation 2x + y − 2z = 1. Show that l is not parallel to Π.[1]
(b)Find the coordinates of the two points on l whose perpendicular distance from Π is 3.[4]
Show answer
(a) Direction · normal = 2 − 1 − 4 = −3 ≠ 0, so l is not parallel to Π.
B1: (1, −1, 2)·(2, 1, −2) = −3 ≠ 0
(b) (−3, 6, −5) and (3, 0, 7)
M1: distance of (1 + t, 2 − t, 3 + 2t) from Π: |2(1 + t) + (2 − t) − 2(3 + 2t) − 1| / 3A1: |−3 − 3t| / 3 = |1 + t|M1: |1 + t| = 3, t = 2 or t = −4A1: (3, 0, 7) and (−3, 6, −5)
Q8Distances (point, plane, skew lines) · Standard · Paper 1 style · 6 marks
(a)In a textile factory in Faisalabad, two straight pipes are modelled as lines. Coordinates are in metres, with the z-axis vertical.Pipe A passes through (0, 0, 3) in the direction 4i + 3j.Pipe B passes through (2, 10, 1) in the direction −j + k.Find the shortest distance between the two pipes, correct to 3 significant figures.[5]
(b)State one assumption made by modelling each pipe as a line.[1]
(b) The thickness (radius) of each pipe is ignored.
B1: pipes have negligible width / are perfectly straight
Q9Distances (point, plane, skew lines) · Challenge · Paper 1 style · 8 marks
(a)The lines l₁: r = 2i + k + λ(i − j + 2k) and l₂: r = 3j − 2k + μ(2i + j − k) are skew. The point P on l₁ and the point Q on l₂ are such that PQ is perpendicular to both lines.Find the coordinates of P and Q.[6]
(b)Find the shortest distance between l₁ and l₂.[2]
Q10Distances (point, plane, skew lines) · Challenge · Paper 1 style · 8 marks
(a)A flat mirror in a physics laboratory lies in the plane Π: 2x − y + 2z = 3 (units are metres). A small light source is at the point S(5, 2, 6).Find the perpendicular distance from S to Π.[2]
(b)Find the coordinates of the image S′ of S in the mirror (the reflection of S in Π).[3]
(c)A camera is at C(1, −3, 2). Find the distance travelled by light that goes from S to the mirror and is reflected to C, using the shortest such path.[3]
Show answer
(a) 17/3 m
M1: |10 − 2 + 12 − 3| / √9A1: 17/3 m
(b) (−23/9, 52/9, −14/9)
M1: line through S along the normal: (5 + 2t, 2 − t, 6 + 2t)M1: meets Π when 9t + 17 = 0, t = −17/9; foot F = (11/9, 35/9, 20/9)A1: S′ = S + 2(F − S) = (−23/9, 52/9, −14/9)
(c) 10.1 m
B1: C is on the same side of Π as S (2(1) − (−3) + 2(2) − 3 = 6 > 0 and 2(5) − 2 + 2(6) − 3 = 17 > 0)M1: shortest path length = |S′C| = √((−23/9 − 1)² + (52/9 + 3)² + (−14/9 − 2)²)A1: 10.1 m
Q11Distances (point, plane, skew lines) · Challenge · Paper 1 style · 7 marks
(a)The lines l₁ and l₂ have equationsl₁: r = i + 2k + s(i + j)l₂: r = pj + k + t(j + k)where p is a constant. Find a vector perpendicular to both lines.[2]
(b)The shortest distance between l₁ and l₂ is 2√3. Find the two possible values of p.[4]
(c)Explain why the lines are skew for both values of p.[1]
Show answer
(a) i − j + k (or any multiple)
M1: (1, 1, 0) × (0, 1, 1)A1: (1, −1, 1)
(b) p = 4 or p = −8
M1: vector between the lines (−1, p, −1)M1: |(−1, p, −1)·(1, −1, 1)| / √3 = 2√3A1: |−p − 2| = 6A1: p = 4 or p = −8
(c) The directions are not parallel and the shortest distance is 2√3 ≠ 0, so the lines do not meet.
B1: non-parallel directions and non-zero distance
Q12Equations of planes · Core · Paper 1 style · 3 marks
(a)Find, in the form ax + by + cz = d, an equation of the plane through the point A(2, −3, 1) that is perpendicular to the vector 4i + j − 5k.[2]
(b)Determine whether the point B(1, 6, 2) lies in this plane.[1]
Show answer
(a) 4x + y − 5z = 0
M1: d = 4(2) + 1(−3) − 5(1)A1: 4x + y − 5z = 0
(b) Yes: 4 + 6 − 10 = 0
B1: substitute: 4(1) + 6 − 5(2) = 0 = d, so B lies in the plane
Q13Equations of planes · Core · Paper 1 style · 5 marks
(a)The points A(2, 1, −1), B(0, 3, 1) and C(1, −2, 4) lie in the plane Π. Find a vector normal to Π.[3]
(b)Hence find the Cartesian equation of Π.[2]
Show answer
(a) 2i + j + k (or any multiple)
M1: AB = (−2, 2, 2), AC = (−1, −3, 5)M1: AB × AC = (16, 8, 8)A1: normal (2, 1, 1)
(b) 2x + y + z = 4
M1: substitute AA1: 2x + y + z = 4
Q14Equations of planes · Core · Paper 1 style · 4 marks
(a)The plane Π has vector equation r = i + 2j + s(i + 3k) + t(2j − k). Find the equation of Π in the form ax + by + cz = d.[3]
(b)Find the point where Π meets the z-axis.[1]
Show answer
(a) 6x − y − 2z = 4
M1: n = (1, 0, 3) × (0, 2, −1) = (−6, 1, 2)A1: normal (6, −1, −2)A1: 6x − y − 2z = 4
(b) (0, 0, −2)
B1: x = y = 0 gives −2z = 4
Q15Equations of planes · Standard · Paper 1 style · 6 marks
(a)The line l has equation r = i + 3k + λ(2i − j + k) and the point P has coordinates (4, 2, −1). Show that P does not lie on l.[2]
(b)Find an equation of the plane that contains l and P, in the form ax + by + cz = d.[4]
Show answer
(a) No single λ fits all three coordinates, so P is not on l.
M1: 1 + 2λ = 4 gives λ = 3/2; then y = −3/2 ≠ 2A1: contradiction, so P is not on l
Q16Equations of planes · Standard · Paper 1 style · 6 marks
(a)The lines l₁: r = 3i − j + 2k + λ(i + 2j − k) and l₂: r = −i + 6j − 9k + μ(2i − j + 3k) intersect. Find the coordinates of their point of intersection.[3]
(b)Find the Cartesian equation of the plane containing l₁ and l₂.[3]
M1: normal = (1, 2, −1) × (2, −1, 3)A1: (5, −5, −5), i.e. normal (1, −1, −1)A1: x − y − z = 2
Q17Equations of planes · Standard · Paper 1 style · 6 marks
(a)The line l has equation r = 2j − k + λ(3i + j + 2k) and the line m has direction vector i − 2j.Write down a vector equation, in the form r = a + λb + μc, of the plane Π that contains l and is parallel to m.[1]
(b)Find the Cartesian equation of Π.[3]
(c)The line m passes through the point (2, 1, 5). Find the distance between m and Π.[2]
Q18Equations of planes · Challenge · Paper 1 style · 8 marks
(a)The lines l₁: r = i + j + λ(2i + j − k) and l₂: r = 3i − 2j + 4k + μ(−4i − 2j + 2k) are parallel. Explain why they are parallel and show that they are distinct.[2]
(b)Find the Cartesian equation of the plane containing both lines.[3]
(c)Find the distance between the two lines.[3]
Show answer
(a) Directions are multiples ((−4, −2, 2) = −2(2, 1, −1)); (3, −2, 4) does not lie on l₁, so they are distinct.
B1: direction of l₂ = −2 × direction of l₁B1: 1 + 2λ = 3 gives λ = 1, then y = 2 ≠ −2, so (3, −2, 4) is not on l₁
(b) x − 10y − 8z = −9
M1: use b and a₂ − a₁ = (2, −3, 4)M1: (2, 1, −1) × (2, −3, 4) = (1, −10, −8)A1: x − 10y − 8z = −9
Q24Angles between lines & planes · Standard · Paper 1 style · 6 marks
(a)A sloping roof panel on a house in Murree is modelled as part of a plane through the points A(0, 0, 3), B(8, 0, 3) and C(4, 5, 6), in metres, where the z-axis is vertical and the ground is z = 0.Find an equation of the plane of the roof panel in the form ax + by + cz = d.[4]
(b)Find the angle between the roof panel and the horizontal ground.[2]
Show answer
(a) 3y − 5z = −15
M1: AB = (8, 0, 0), AC = (4, 5, 3)M1: AB × AC = (0, −24, 40)A1: normal (0, 3, −5)A1: 3y − 5z = −15
Q25Angles between lines & planes · Challenge · Paper 1 style · 7 marks
(a)The planes Π₁: 2x + y + z = 3 and Π₂: x + ky − z = 5, where k is a constant, meet at an angle of 60°. Show that k satisfies k² − 4k + 4 = 0, and hence find k.[4]
(b)For this value of k, find a vector equation of the line of intersection of Π₁ and Π₂.[3]
Q28Lines & planes: intersection, parallel · Standard · Paper 1 style · 5 marks
(a)The line l has equation r = 3i + j − 2k + λ(2i + k) and the plane Π has equation x + 4y − 2z = 5. Show that l is parallel to Π and does not lie in Π.[3]
(b)Find the distance between l and Π.[2]
Show answer
(a) b·n = 2 + 0 − 2 = 0, so l ∥ Π; the point (3, 1, −2) gives 3 + 4 + 4 = 11 ≠ 5, so l is not in Π.
M1: (2, 0, 1)·(1, 4, −2) = 0A1: parallelB1: (3, 1, −2) does not satisfy the plane equation (11 ≠ 5)
(b) 2√21/7 ≈ 1.31
M1: |11 − 5| / √21A1: 6/√21 = 2√21/7
Q29Lines & planes: intersection, parallel · Standard · Paper 1 style · 6 marks
(a)Find a vector equation of the line of intersection of the planes x + 2y + z = 4 and 2x − y + 3z = 1.[4]
(b)Find the point where this line meets the plane x + y + z = 6.[2]
M1: direction = (1, 2, 1) × (2, −1, 3) = (7, −1, −5)A1M1: common point, e.g. z = 0: x + 2y = 4, 2x − y = 1A1: (6/5, 7/5, 0); r = (6/5)i + (7/5)j + t(7i − j − 5k)
(b) (25, −2, −17)
M1: substitute general point; t = 17/5A1: (25, −2, −17)
Q30Lines & planes: intersection, parallel · Challenge · Paper 1 style · 8 marks
(a)The line l has equation r = i + pj + 2k + t(2i − j + k), where p is a constant, and the plane Π₁ has equation x + 3y + z = 9.Show that l is parallel to Π₁ for every value of p.[1]
(b)Find the value of p for which l lies in Π₁.[2]
(c)For the value of p found in (b), the plane Π₂ contains l and is perpendicular to Π₁. Find the Cartesian equation of Π₂.[3]
(d)For p = 5, find the distance between l and Π₁.[2]
Show answer
(a) (2, −1, 1)·(1, 3, 1) = 0
B1: direction · normal = 2 − 3 + 1 = 0
(b) p = 2
M1: (1, p, 2) in Π₁: 1 + 3p + 2 = 9A1: p = 2
(c) 4x + y − 7z = −8
M1: normal of Π₂ is perpendicular to both (2, −1, 1) and (1, 3, 1)A1: (2, −1, 1) × (1, 3, 1) = (−4, −1, 7)A1: through (1, 2, 2): 4x + y − 7z = −8
(d) 9/√11 = 9√11/11 ≈ 2.71
M1: |1 + 15 + 2 − 9| / √11A1: 9/√11
Similar questions
Questions that test the same subtopic in different years, grouped so you can work on one skill at a time.
References only: find each question in its paper (official link where available, otherwise through your school).