Unit 7

Vectors

1. In the diagram in the answer space AB represents the column vector (41) and BC represents the column vector (23).

A B C

(a) Mark clearly on the diagram, and label, the point D such that ABCD is a parallelogram.

(b) Write down AD in column vector form.

(c) Write down CA in column vector form.

2. (a) In the diagram, T is the mid-point of AB and M is the mid-point of AT. Given that OA=a and OB=b, express as simply as possible in terms of a and b,

O A M T B a b

(i) AB,

(ii) AM,

(iii) OM.

(b) Two points P and Q have position vectors p and q respectively, relative to the origin O. Given that p=(53) and PQ=(21), find

(i) q,

(ii) |PQ|,

(iii) the coordinates of the point R, which is such that OR=QP. Given also that s=(11), t=(82) and lp+ms=t, write down two simultaneous equations in l and m, and solve them.

3. Given that OA=(p4) and OB=(50), find

(a) the value of |OB|,

(b) a value for p if OA and OB are two sides of a rhombus.

4. OABC is a parallelogram where O is the origin, OA=(14) and OC=(52).

(a) On the diagram in the answer column mark and clearly label the points A, B, and C.

0 2 4 6 y 2 4 6 x

(b) Express as a column vector

(i) OB,

(ii) CA.

5. In the diagram OP=a and OS=b.

O P Q S R X a b

(a) Express SP in terms of a and b.

(b) Given that SX=hSP, show that OX=ha+(1h)b.

(c) Given that OQ=3a and QR=2b, write down an expression for OR in terms of a and b.

(d) Given that OX=kOR use the results of parts (b) and (c) to find the values of h and k.

(e) Find the numerical value of the ratio PXXS.

6. It is given that u=4a+3b, v=5ab and w=ha+(h+k)b, where h and k are constants. If w=3u2v, calculate the value of h and of k.

7. In the diagram, M and N are the midpoints of AD and DC respectively. It is given that AB=BC=a and that BD=a+b. Write down, as simply as possible in terms of a and/or b, expressions for

A B C D M N a a a + b

(a) AD,

(b) DC,

(c) MN.

8. (a) Given that OK=(162), OL=(43) and that M and N are the midpoints of OK and OL respectively,

O B P A 4b 4a 3a − b

(i) express MN as a column vector,

(ii) find the value of |KL|.

(b) Given that OA=4a, OB=4b and BP=3ab, express as simply as possible, in terms of a and b,

(i) OP,

(ii) AP.

The lines OA produced and BP produced meet at Q. Given that BQ=mBP and OQ=nOA, form an equation connecting m, n, a and b.

9. (a) The vectors r and s are defined by r=(24) and s=(13).

(i) Evaluate |r|.

(ii) If r+2t=6s, express t as a column vector.

(b) In the triangle ABC, X is the midpoint of AB.

A B C X Y Z

(i) Given that AB=p and AC=q, express the following vectors in terms of p and/or q, giving your answers in their simplest form.

(I) AX,

(II) CX.

(ii) Given that Z is the point on XC such that XZ=23XC and that YC=kAC, express YZ in terms of k, p and q.

(iii) If, in addition, YZ is parallel to AX, find the numerical value of

(I) k,

(II) ABYZ,

(III) Area of ΔArea of ΔYZCABC.

10. AB=(3−4), AC=(u12) and AD=(8v).

(a) Given that C lies on AB produced, write down the value of u.

(b) Given that AD is perpendicular to AB, calculate the value of v.

11. In the diagram, OP=p, OQ=q and PX=XQ.

O P Q R X p q

(a) Express in terms of p and q

(i) PX,

(ii) OX.

(b) Given that OR=34p+34q, write down the numerical value of the ratio RXXO.

(c) QR is produced to point Y where QY=kQR. Obtain expressions for QR and QY and hence prove that OY=3h4p+(1h4)q.

(d) Given also that OY=kOP, form an equation involving p, q, h and k and use it to find the value of h and k.

(e) Deduce the numerical value of the ratio YPPO.

12. The diagram in the answer space shows the origin O and three points A, B and P. The position vectors of A and B with respect to O are a and b. Given that another point Q is such that OQ=ha and QP=kb,

(a) mark on the diagram, and label clearly, the point Q,

(b) determine the value of

(i) h,

(ii) k.

13. In the diagram, PQRS is a straight line and PQ=QR=RS. Given that OQ=2x+y and PO=yx, express, as simply as possible, in terms of x and/or y,

O P Q R S 2x + y y − x

(a) RQ,

(b) OP,

(c) OS.

14. It is given that A is the point (2,0), B is the point (7,0) and BC=(32). Find

(a) |AB|,

(b) the coordinates of the point C,

(c) the gradient of the line AC.

15. (a) Given that p=(32) and q=(24),

(i) express 3p12q as a column vector,

(ii) find |q|.

(b) In the diagram, PA=5a, PB=10b and X is a point on AB such that AXXB=23. Express in terms of a and b, as simply as possible,

Y A P C B X 10b 5a 6a − 2b

(i) AB,

(ii) AX,

(iii) PX.

The line PX is produced to C such that BC=6a2b.

The lines PA and BC are produced to intersect at Y.

(iv) Given that BYBC=k, express BY in terms of k, a and b.

(v) Given that PYPA=r, express PY in terms of r, a and b.

(vi) Using the expressions for PB, BY and PY, form an equation connecting k, r, a and b. Use this equation to find the values of k and r.

16. ABCD is a parallelogram, M is the midpoint of BC and L is a point on AD such that 3AL=LD. Given that AB=p and BM=2q, express as simply as possible, in terms of p and/or q,

A L D B M C p 2q

(a) MD,

(b) DL,

(c) LM.

17. It is given that A is the point (3,4), B is the point (12,10) and P is the point on AB such that AP=12PB.

(a) Express as column vectors

(i) AB,

(ii) AP,

(iii) the position vector of P relative to the origin O.

(b) If O, A and B are three of the vertices of a parallelogram, find the coordinates of two possible positions of the fourth vertex.

18. It is given that OA=(34), AB=(9n) and OB=(2mm).

Find the value of

(a) |OA|,

(b) m,

(c) n.

19. In the triangle ABC, P is the mid-point of BC. The line RQ is drawn parallel to BC intersecting AP at G. Given that AG=2p, GP=p and GQ=2q, express the following as simply as possible in terms of p and/or q.

A B C P R Q G 2p p 2q

(a) PC,

(b) AC,

(c) PR.

20. In the diagram, M is the midpoint of XZ, OX=p+2q, OZ=7p2q and ZY=3kqp, where k is a constant.

O Z X Y M p + 2q 7p − 2q 3kq − p

(a) Express as simply as possible in terms of p and/or q.

(i) XZ,

(ii) XM,

(iii) OM.

(b) Express OY in terms of p, q and k.

(c) If Y lies on OM produced, find the value of k.

21. (a) The diagram shows three vectors OA, OB and OC. Given that OT=OA+2OB3OC, mark the point T on the diagram, and label it clearly.

A B C O

(b) The column vectors u, v and w are defined by

u=(104),    v=(25),    w=(pq).

(i) Express 12u+3v as a column vector.

(ii) Given also that uw=wv, find the value of p and the value of q.

22. OABC is a parallelogram and M is the midpoint of BC. OC is produced to D so that OC=CD. OM is produced to meet DB at N.

(a) Given that OA=2p and AB=2q, express the following vectors in terms of p and q, giving each of your answers in its simplest form.

(i) OB,

(ii) OM,

(iii) BD.

(b) Given that ON=hOM and that BN=kBD, use the fact that ON=OB+BN to write down an equation in terms of h, k, p and q. Hence show that h=43 and find the value of k.

O A B C D M N 2p 2q

(c) Find the numerical value of

(i) OMON,

(ii) the area of Δthe area of ΔMDOMDN,

(iii) the area of Δthe area of trapeziumOBDOABD.

23. PQ=(24), QR=(86). Find

(a) PR,

(b) RX, given that 2RX=QR,

(c) |QR|.

24. ABCD is a parallelogram in which AB=p and BC=q. The point E on AD is such that AE=14AD.

A E D B F C p q

(a) Express, in terms of p and/or q,

(i) AC,

(ii) AE,

(iii) BE.

(b) AC and BE intersect at F. Given that BF=kBE, express BF in terms of p, q and k.

(c) Hence show that AF=(1k)p+14kq.

(d) Given also that AF=hAC, express AF in terms of p, q and h.

(e) Using these two expressions for AF, find the value of h and the value of k.

(f) Find the ratio AF:FC.

25. The vectors AB and CD are such that AB=(68) and CD=(u2).

(a) Find |AB|.

(b) Given that CD is parallel to AB, find the value of u.

26. In the diagram, OP=p, OQ=q and R is the point on PQ such that PR=34PQ.

O P Q R p q

(a) Express as simply as possible in terms of p and q,

(i) PQ,

(ii) PR,

(iii) OR.

(b) Given that S is the point such that PS=3q and that OS=kOR,

(i) draw a sketch to show the approximate position of S,

(ii) find the value of k,

(iii) write down the numerical value of the ratio OR:RS.

27. P is the point (3,4) and Q is the point (11,10).

(a) Calculate the coordinates of the midpoint of PQ.

(b) Express PQ as a column vector.

(c) Find the value of |PQ|.

28. (a) The point O lies inside square PQRS. Given that OP=(42) and OQ=(35), express as column vectors

P Q R S O

(i) PQ,

(ii) RS,

(iii) QR.

(b) OAX and OBZ are straight lines and AZ intersects BX at Y. OB=BZ and AYYZ=12. Given that OA=3a and OB=3b, express as simply as possible in terms of a and b,

O A X Y B Z

(i) AZ,

(ii) AY,

(iii) OY,

(iv) BY.

Given that BX=hBY, write down an expression for BX and show that OX=2ha+(3h)b. Given also that OX=kOA, form an equation involving a, b, h and k and use it to find k. Hence write down the numerical value of the ratio OAOX.

29. p=(68), q=(54), r=(9k).

(a) Express p+2q as a column vector.

(b) Find |p|.

(c) Given that r is parallel to p, find the value of k.

30. ABCD is a parallelogram. The point E, on BD, is such that BE=14BD.

A D B X C E 4p 4q

(a) Given that AB=4p and AD=4q, express, in terms of p and/or q,

(i) CD,

(ii) BD.

(b) Show that AE=3p+q.

(c) The point X lies at the point of intersection of BC and AE produced, so that AX=43AE. Given that BX=hBC, find the value of h.

(d) Find the numerical value of BXXC.

31. It is given that a=(34) and b=(11).

(a) Find a+b.

(b) Calculate |a|.

(c) If a=3b+2c, express c as a column vector.

32. AB=(86) and CD=32AB.

(a) Calculate |AB|.

(b) Express CD as a column vector.

(c) Given that A is the point (6,9) find the coordinates of the point B.

(d) Given that D is the point (1,4) find the coordinates of the point C.

33. In the diagram, OA=3x, OB=2x+y and OC=2y.

O A D C B 2y 2x + y 3x

(a) Express CO in terms of y.

(b) The point D is such that OD=hOA. Show that CD=3hx2y.

(c) Express CB in terms of x and y, giving your answer in its simplest form.

(d) Given also that CD=kCB, write down an equation in terms of x, y, h and k.

(e) Find the value of h and the value of k.

(f) Find AD.

34. The diagram shows the positions of the points X, P and Q where PQ=(42).

P Q

(a) Y is the point such that PQYX is a parallelogram. Express QY as a column vector.

(b) Z is the point such that PQXZ is a parallelogram. Express XZ as a column vector.

(c) R is the midpoint of PQ. Express XR as a column vector.

35. OPQR is a parallelogram. M is the midpoint of PQ and N is the midpoint of QR. OP=2a and OR=2b.

O R P Q M N X 2a 2b

(a) Express in terms of a and/or b

(i) PM,

(ii) OM,

(iii) ON,

(iv) PN.

(b) OM and PN meet at X. Given that PX=hPN, express PX in terms of a, b and h.

(c) Hence show that OX=(2h)a+2hb.

(d) Given also that OX=kOM, express OX in terms of a, b and k.

(e) Using these two expressions for OX, find the value of h and the value of k.

(f) Find the ratio XN:PN.

36. X lies on the straight line AB and AX:XB=1:3. With respect to an origin O, the position vector of A is 4p and the position vector of B is 4q. Express in terms of p and q,

O A X B 4p 4q

(a) AB,

(b) AX,

(c) OX, giving this last answer in its simplest form.

37. (a) It is given that p=(65), q=(43) and r=(ab).

(i) Find |q|.

(ii) Express 2p+3q as a column vector.

(iii) Given that pq=2r, find the value of a and the value of b.

(b) ABCD is a quadrilateral in which AB=2s, DC=6s and DA=2t.

(i) Sketch the quadrilateral ABCD.

(ii) Consider the pair of sides AB and DC. Write down two important facts about this pair of sides.

(iii) Express BC, as simply as possible, in terms of s and/or t.

(iv) The sides DA and CB, when produced, meets at X. Express XA, as simply as possible, in terms of s and/or t.

38. OABC is a parallelogram. The point X on AC is such that AX=15AC. The point Y on AB is such that AY=14AB. Given that OA=20p and OC=20q, express in terms of p and q

(a) AC,

(b) AX,

(c) OX,

(d) OY.

What do the results of (c) and (d) tell you about O, X and Y?

39. In the diagram, AC is parallel to OD, A is the midpoint of OB and X is the point on AD such that AX=13AD. OA=(50) and OD=(86).

O A B D C X

(a) Find the value of |OD|.

(b) Express each of the following as a column vector:

(i) CA,

(ii) AD,

(iii) BX.

40. The diagram represents an equilateral triangle ABC with sides of length 12 cm. M is the midpoint of AC, and CT=4 cm. It is given that CB=3p and MC=q.

B A C M X T 3p q

(a) Express, as simply as possible, in terms of p and/or q,

(i) AC,

(ii) CT,

(iii) AT,

(iv) MB.

(b) X is the point where BM intersects AT.

(i) Given that MX=hMB, show that AX=3hp+(h+1)q.

(ii) Given also that AX=kAT, form an equation involving p, q, h and k.

(iii) Use this equation to find the value of h.

(iv) By using the Pythagoras' Theorem in ΔABM, calculate BM. Hence write down the length of XM, giving your answer in centimetres correct to one decimal place.

41. AB=(86).

(a) Calculate |AB|.

(b) Given that A is the point (7,3), find the coordinates of the point B.

(c) It is given that CD is parallel to AB and that it is half as long as AB. Express CD as a column vector.

42. In the diagram, XVZ is a straight line, XY=8p, XZ=4p+9q and YV=6p+cq.

X Y Z V 4p + 9q 8p -6p + cq

(a) Express VZ in terms of p, q and c.

(b) Given that YV=hYZ, form an equation involving p, q, h and c, and use it to find the numerical values of h and c.

(c) The point K is outside triangle XYZ and is such that XK=4p+3q. Is XK parallel to YV? Justify your answer.

43. PO=(47), QR=(12), RS=(h10.5).

(a) Express as a column vector PQ+3QR.

(b) Given that RS is parallel to PQ, find the value of h.

(c) Find |PQ|, giving your answer correct to the nearest whole number.

44. In the diagram, the lines ST, PQ and OR are parallel. OPS, OQT and RQS are straight lines.

O P S R Q T b 2b 3a 2a + b

(a) Given that OR=3a, OP=b, PS=2b and OQ=2a+b express, in terms of a and/or b,

(i) PQ,

(ii) QR,

(iii) QT,

(iv) ST.

(b) Find the numerical value of

(i) the area of ΔOPQthe area of ΔSPQ,

(ii) the area of ΔOPQthe area of ΔQST,

(iii) the area of ΔOPQthe area of ΔORQ.

45. In the diagram, AB=p, AC=q and X is the point on CB such that CX=13CB.

A B C X q p

(a) Express as simply as possible in terms of p and/or q,

(i) CB,

(ii) AX.

(b) Given further that AX=hp+kq, and that T is the point such that AT=hp, mark and label the point T on the diagram in the answer space.

A B C X

46. In the diagram, OP=a, OQ=b and X is the point on PQ such that PX=14PQ.

P Q O X a b

(a) Express as simply as possible in terms of a and/or b,

(i) PQ,

(ii) OX.

(b) Given further that OX=ha+kb, and that N is the point such that ON=ha, mark and label the point N on the diagram in the answer space.

P Q O X

47. AB=(68).

(a) Calculate |AB|.

(b) Given that ABCD is a parallelogram, express CD as a column vector.

(c) Given that A is the point (7,3) and that M is the midpoint of AB, find the coordinates of M.

48. In the diagram OA=13OP, and OB=14OQ. M is the midpoint of OQ, and MX=15MP.

O B M Q A P X a b

(a) Given that OA=a and OB=b express, as simply as possible, in terms of a and/or b,

(i) OP,

(ii) OM,

(iii) AQ,

(iv) MP,

(v) MX,

(vi) AX.

(b) Prove that AX, when produced, will pass through Q.

(c) Find the ratio AX:XQ.

(d) Given that the area of ΔOPQ is 30 cm², calculate the area of

(i) ΔPMQ,

(ii) ΔPQX,

(iii) ΔOAB.

49. It is given that OP=p and OQ=q. R, S, T and U are points on the grid. Express, in terms of p and/or q,

O P Q R S T U p q

(a) OR,

(b) OS,

(c) OT,

(d) OU.

50. In triangle ORS, the point A on OR is such that OA=2AR. B is the midpoint of OS, X is the midpoint of AB and OX produced meets RS at Y. OA=2p and OB=2q.

O R S A B X Y 2p 2q

(a) Express in terms of p and/or q

(i) AB,

(ii) AX,

(iii) OX,

(iv) RS.

(b) Given that RY=hRS, express RY in terms of p, q and h.

(c) Hence show that OY=3(1h)p+4hq.

(d) Given also that OY=kOX, express OY in terms of p, q and k.

(e) Using these two expressions for OY, find the value of h and the value of k.

(f) Find the ratio RY:YS.

(g) Express XY in terms of p and q.

51. AB=(71), BC=(25).

(a) Express AC as a column vector.

(b) D is the point (2,1) and E is (h,6).

(i) Express DE as a column vector.

(ii) If DE is parallel to AB, find the value of h.

(iii) If instead, |DE|=|AB|, find the two possible values of h.

52. In the diagram, ABCD is a parallelogram, X is the midpoint of AC, Y is the midpoint of AX and W is the point on AD such that AW=2WD.

A B C D P Y X W 3q

(a) Given that AB=p and AD=3q express, as simply as possible, in terms of p and/or q,

(i) AC,

(ii) AY,

(iii) BY,

(iv) XW.

(b) What do your answers to (a)(iii) and (a)(iv) tell you about BY and XW?

(c) What is the special name given to the quadrilateral BXWY?

(d) Write down the value of each of the following.

(i) ΔABYΔBCY,

(ii) ΔBCYΔAXW.

53. OA=(21) and OB=(34).

(a) Given that OC=OA+OB, express OC as a column vector.

(b) Express AB as a column vector.

(c) If LM=(42), what is the special name given to the quadrilateral ALMO?

54. In the diagram OA=2p, OB=3q and BX=pq. The lines OX and AB intersect at L.

O B X A L 3q 2p p − q

(a) Express as simply as possible in terms of p and/or q

(i) OX,

(ii) AB.

(b) Given that AL=hAB, express AL in terms of p, q and h.

(c) Hence show that OL=(22h)p+3hq.

(d) Given also that OL=kOX, form an equation involving p, q, h and k and use it to find the numerical value of h.

55. Given that OP=u, OQ=v and PR=w, express QR in terms of u, v and w.

56. Given that P is the point (1,1), PQ=(32), PR=(54) and that T is the midpoint of QR, find

(a) QR,

(b) PT,

(c) the coordinates of the point X such that PQXR is a parallelogram.

57. The grid in the working space is provided for you to use if you wish. P is the point (1,1) and Q is the point (3,2).

(a) Write down PQ as a column vector.

(b) The line PQ is mapped onto the line P1Q1 by an enlargement of scale factor 3.

(i) Write down P1Q1 as a column vector.

(ii) Given that P1 is the point (1,5), find the coordinates of the centre of the enlargement.

58. In the diagram QR=4QS and SP=5SX. T is the midpoint of PR. QS=a and RT=b.

Q P R S T X a b

(a) Express, as simply as possible, in terms of a and/or b,

(I) SR,

(II) SP,

(III) SX.

(b) Show that QX=25(4a+b).

(c) Express QT as simply as possible, in terms of a and b.

(d) Calculate the value of

(i) QXQT,

(ii) ΔPQXΔPQT,

(iii) ΔPQXΔPQR.

59. The grid below is provided for you to use in this question, if you wish.

C is the point (1,2) and D is the point (4,3).

(a) Write down CD as a column vector.

(b) The line CD is mapped onto the line C1D1 by an enlargement of scale factor 3.

(i) Write down C1D1 as a column vector.

(ii) Given that C1 is the point (1,6), find the coordinates of the centre of the enlargement.

60. In the diagram, A is (0,4), B is (3,6) and O is the origin.

O A B y x

(a) Express AB as a column vector.

(b) Calculate the coordinates of the point D, where BD=2AB.

(c) AC=(52).

(i) Calculate the length of AC.

(ii) Write down the gradient of the line AC.

(iii) Write down the equation of the line AC.

(iv) The point E lies on AC and EB is parallel to the y-axis. Calculate the coordinates of E.

61. The quadrilateral ABCD is such that AB=2p, BC=q and CD=3p.

(a) What is the special name given to the quadrilateral ABCD?

(b) Express DA in terms of p and q, giving your answer in its simplest form.

62. OACB is a quadrilateral. OB is parallel to AC. D is the point on BC such that BD=13BC. The lines OB and AD produced meet at F.

O A B C D F

(a) Given also that AC=(86), calculate the value of |BF|.

(b) Given also that OB=AC, and OA=(52), express FC as a column vector.

63. In the diagram, OABCDE is a regular hexagon. OA=a and OC=c. Express the following vectors, as simply as possible, in terms of a and/or c.

O A B C D E a c

(i) CD,

(ii) AC,

(iii) OB.

64. On the grid in the answer space OA=a and OB=b. The point Y is also marked.

O A B Y a b

(a) On the grid mark clearly the point X, such that OX=3b2a.

(b) Write down OY in terms of a and b.

(c) It is given that OP=a+nb, where n takes all values from 3 to 3. On the grid draw the locus of P.

65. On the grid in the answer space OP=p and OQ=q. The point R is also marked.

O P Q R p q

(a) Write down OR in terms of p and q.

(b) On the grid mark clearly the point S, such that OS=2p3q.

(c) It is given that OT=np+2q, where n takes all values from 3 to 4. On the grid draw the locus of T.

66. On the grid in the answer space, OP=p and OQ=q.

O P Q p b

(a) Mark clearly on the grid the point X such that OX=2p and the point Y such that OY=2p3q.

(b) What is the special name given to the quadrilateral OQXY?

67. (a) Given that AB=(23), BC=(01) and CD=(51), find DA.

68. In the diagram, OABC is a parallelogram. The position vectors of the points A and B are given by OA=(51), OB=(86).

O A B C y x

(a) Find |OB|.

(b) Express as column vectors

(i) AB,

(ii) CA.

(c) The point P lies on CA produced and AP=hCA.

(i) Show that OP=(5+2h14h).

(ii) Given that P lies on the x-axis, find

(a) the value of h,

(b) the coordinates of P.

69. In the diagram, OPQR is a rhombus. The position vectors of the points P and R are given by OP=(25) and OR=(52).

O P Q R y x

(a) Express as column vectors

(i) PQ,

(ii) OQ,

(iii) PR.

(b) The point S lies on PR produced and RS=kPR.

(i) Show that OS=(5+3k23k).

(ii) Given that S lies on the x-axis, find

(a) the value of k,

(b) the coordinates of S.

70. Given that u=(68), v=(910) and w=(15p), find

(a) (i) |u|,

(ii) 2u+v.

(b) Given that the vector w is parallel to the vector u, calculate the value of p.

71. In the diagram, OA=(86) and OB=(32).

(a) Find

(i) |OA|,

(ii) BA.

(b) Given that BC=(x9) and BC=kOA,

find the value of

(i) k,

(ii) x,

(iii) the ratio area of triangle OABarea of triangle ACB.

O A B

72. In the diagram, OP=(43) and OQ=(86).

O P Q

(a) Find

(i) |OP|,

(ii) PQ,

(iii) QP.

(b) Given that PR=(6y) and PR=kOQ, find the value of

(i) k,

(ii) y.

73. A is the point (7,3) and B is the point (5,11). Find

(a) the coordinates of the midpoint of AB,

(b) the vector AB.

74. (a) p=(43), q=(29) and r=(12).

(i) Find |q|.

(ii) Express as a column vector

(a) 2p+q,

(b) p2r.

(iii) Write down two facts about the vectors 2p+q and p2r.

(b)

O A M B N C a b

In the diagram, OA=a and OB=b. OM=3OA and ON=2OB. C is the point on MN produced where MN=NC.

(i) Express, as simply as possible, in terms of a and/or b,

(a) MO,

(b) MN,

(c) AB,

(d) AC.

(ii) Write down two facts which your answers to (c) and (d) tell you about A, B and C.

75. p=(14), q=(34) and r=(m2).

(a) Find |q|.

(b) Express 2pq as a column vector.

(c) Given that p is parallel to r, find m.

76. p=(43), q=(21) and r=(k3).

(a) Find |p|.

(b) Express 3qp as a column vector.

(c) Given that q is parallel to r, find k.

77. In the diagram, AD=p, DB=q and AC=2AD.

A B D C p q

(a) Express, as simply as possible, in terms of p and q,

(i) AB,

(ii) CB.

(b) E is a point such that BE=p.

(i) Express AE in terms of p and q.

(ii) Explain why ABEC is a trapezium.

(c) Given that |p|=8, |q|=7 and AD^B=57, calculate

(i) the perpendicular distance from B to AD,

(ii) the area of the trapezium ABEC,

(iii) the length of AB.

78. In the diagram, OAB is a triangle.

C is the point on AB such that AC:CB=2:1.
The side OB is produced to the point D such that OB:BD=3:2.

It is given that OA=a and OB=b.

O A B D C E a b

(a) Express, as simply as possible, in terms of a and/or b,

(i) AB,

(ii) AC,

(iii) OC,

(iv) OD.

(b) Show that CD=b13a.

(c) It is given that E is the point on OA such that OE=59a.

Express, as simply as possible, in terms of a and b, the vector ED.

(d) (i) Show that ED=kCD, where k is a constant.

(ii) Write down two facts about ED and CD.

(e) Calculate the area of Δ AECthe area of Δ OEC.