Mathematics Grade 12 IEB Paper 2 2017 Question Paper

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE EXAMINATION NOVEMBER 2017 MATHEMATICS: PAPER II EXAMINATION NUMBER Time: 3 hours 150 marks PLEASE READ THE FOLLOWING INSTRUCTIONS CAREFULLY 1. This question paper consists of 25 pages and an Information Sheet of 2 pages (i–ii). Please check that your question paper is complete. 2. Read the questions carefully. 3. Answer ALL the questions on the question paper and hand this in at the end of the examination. Remember to write your examination number on the space provided. 4. Diagrams are not necessarily drawn to scale. 5. You may use an approved non-programmable and non-graphical calculator, unless otherwise stated. 6. Ensure that your calculator is in DEGREE mode. 7. All the necessary working details must be clearly shown. Answers only will not necessarily be awarded full marks. 8. It is in your own interest to write legibly and to present your work neatly. 9. Round off to two decimal places unless otherwise stated. FOR OFFICE USE ONLY: MARKER TO ENTER MARKS Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 TOTAL 7 14 18 11 12 15 12 14 8 12 12 15 /150 IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 2 of 25 SECTION A QUESTION 1 A study is done with twelve employees in a company to understand the relationship between the number of rest days given in a year and the productivity of each employee. The results are shown in the table below: (a) Calculate the correlation coefficient. (Round off correct to four decimal places.) (2) (b) Refer to your correlation coefficient and circle the letter that best describes the relationship. Only one letter must be circled. A Fairly strong, negative correlation B Very weak, positive correlation C Fairly strong, positive correlation D Perfect, positive correlation (1) (c) If the equation of the least squares regression line is y = A + Bx, calculate the values of A and B. Give answers correct to four decimal places. (2) (d) Should the regression line in (c) be used to predict the productivity of an employee if thirty rest days were given to the employee in a year? (Explain your answer.) (2) [7] IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 3 of 25 QUESTION 2 In the Cartesian plane below, OAB with O(0;0), A(2;4) and B(6;0) is drawn. (a) ˆ Calculate the gradient of OA and hence the size of AOB. (4) IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 4 of 25 (b) Determine the equation of the perpendicular bisector of OA. (4) (c) Write down the equation of the perpendicular bisector of OB. (1) (d) Determine the equation of the circle passing through O, A and B. (5) [14] IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 5 of 25 QUESTION 3 (a) If sin 31°.cos 22° + sin 22°.cos 31° = k, then without the use of a calculator, determine the value of the following in terms k: (1) sin 53° (1) (2) cos 143° (2) (3) sin 75°.sin 22° + cos 75°.cos 22° (3) IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 6 of 25 cos θ cos 2θ (b) Prove that  = sin θ. sin 2θ 2 sin θ (6) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 7 of 25 (c) Calculate the general solution for θ if 3 sin2 θ = 2 sin θ. Give answer correct to one decimal place. (6) [18] IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 8 of 25 QUESTION 4 In the Cartesian plane below, circle centre M is drawn.  A is a point on the x-axis.  Point B lies on the circle and the x-axis.  Point C lies on the circle and the y-axis.  The equation of the circle is (x – 3)2 + (y + 1)2 = 25.  Line AC is a tangent to the circle at C. (a) Write down the coordinates of M. (1) (b) Determine the coordinates of point C. (3) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 9 of 25 (c) Determine the equation of the tangent AC. (3) (d) Determine the length of AB. Leave your answer correct to one decimal place. (4) [11] IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 10 of 25 QUESTION 5 (a) Prove the theorem that states the angle between a tangent and a chord is equal to the angle in the alternate segment. Given: DE is a tangent to circle centre O at A. B and C are points on the circle. Required to prove: (1) Construction: (1) Proof: (5) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 11 of 25 (b) In the diagram below, two circles are drawn intersecting at B and F.  CF is a tangent to the smaller circle at F.  A and G are points on the circumference of the smaller circle.  Chords FC and BD of the larger circle intersect at E.  ABD is a straight line.  Ĉ = 70° and D̂ = 52°. Determine the size of Ĝ 1 . (5) [12] IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 12 of 25 QUESTION 6 A number of learners were asked how many WhatsApp messages they sent during a day. The results are summarised in the table and the cumulative frequency curve given below. WhatsApp Frequency messages sent 50  x < 100 20 100  x < 150 30 150  x < 200 P 200  x < 250 M 250  x < 300 80 300  x < 350 70 350  x < 400 50 (a) What is the value of A on the horizontal axis of the cumulative frequency curve? (1) (b) How many learners were asked for information? (1) (c) Determine the values of P and M in the table above. (2) (d) Calculate the interquartile range. (3) (e) Calculate an estimate for the mean WhatsApp messages sent per day. (2) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 13 of 25 (f) If the cellphone company introduced a contract where you were not allowed to send more than 300 WhatsApp messages per day then: (1) How would this affect the median? Explain. (2) (2) How would this affect the standard deviation? Explain. (2) (3) In which direction would the data be skewed? Explain. (2) [15] 77 marks IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 14 of 25 SECTION B QUESTION 7 In the diagram below, AOC with A(2;6) and O(0;0) is drawn.  C is a point on the x-axis.  AO = AC.  E lies on the y-axis and F lies on the x-axis.  Line EF goes through the points B and D on OA and CA respectively.  The equation of EF is given by 2y + x = 10. (a) Determine the coordinates of B and hence the area of ΔEBO. (8) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 15 of 25  18  (b) If D  x;  , determine the area of ΔDCF.  5  (4) [12] IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 16 of 25 QUESTION 8 In the Cartesian plane below, circle centre O(3;1) is drawn.  A and C(0;–2) are fixed points on the circle.  ˆ = 30. CAB  B is a variable point on the circle. (a) (1) Determine the length of OC. (2) (2) B moves along the circle until BC is parallel to the x-axis. Write down the new coordinates of B. (2) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 17 of 25 (3) ˆ for this new position of B. Give all Calculate the size of CAB reasons. (4) (b) B moves from its original position along the circle in an anti- 9 clockwise direction until the area OBC = square units. 2 Find the shortest distance that B has to move along the circle for the above to occur. (6) [14] IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 18 of 25 QUESTION 9 In the diagram below, a circle passing through A, B and D is drawn.  CD is a tangent to the circle at D. (a) Prove that ΔADC ||| ΔDBC. (4) (b) Show that AB.BC = DC2 – BC2. (4) [8] IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 19 of 25 QUESTION 10 In the diagram below, two circles touch internally at A.  AB is the diameter of the larger circle and AL is the diameter of the smaller circle.  S and L are the centres of the circles.  D is a point on the smaller circle and C is a point on the larger circle. ADC is a straight line.  M is a point on LB so that MN || LC. (a) Prove that DL || CB. (4) IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 20 of 25 (b) Prove that 2SD = LC. (3) SL (c) Determine the value of . AB (2) BN 7 (d) If AB = 30 units and = , then determine the length of LM. NC 9 (3) [12] IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 21 of 25 QUESTION 11 (a) In the diagram below, a circle with centre O is drawn.  OD  AC and OD and AC intersect at E.  A, B, C and D lie on the circumference of the circle. (1) Determine the length of BE in terms of AO and ED. (2) (2) Prove that (2AO – ED)2 = BC2 – AE2. (4) IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 22 of 25 (b) In the diagram below, a circle is drawn passing through A, B, C and D.  ˆ = θ. BED  BE and ED are tangents at B and D respectively. ˆ = 90 + θ . Prove that BCD 2 (6) [12] IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 23 of 25 QUESTION 12 (a) In the diagram below, three EQUAL circles of radius 3 units are positioned so that they touch each other. BT is a vertical common tangent to two circles and CD is a horizontal common tangent to the same circles. Show that the length of BT = 3 3  6 . (5) IEB Copyright © 2017 PLEASE TURN OVER

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 24 of 25 (b) Three identically sized cylinders are stacked on top of each other as shown in the diagram below. They are anchored down by a piece of rope from A to B and another piece of rope from B to E.  A, C, D and E lie on the same horizontal plane.  B, C and D lie on the same vertical plane.  B is the highest point on the cylinder.  The angle of elevation from A to B is 50°.  ˆ = 70°. BEA  The radius of each cylinder is 3 metres. (1) Calculate the length of AB (the rope required to anchor the cylinder down). (4) IEB Copyright © 2017

Downloaded from hlayiso.com NATIONAL SENIOR CERTIFICATE: MATHEMATICS: PAPER II Page 25 of 25 (2) If the second rope EB has a length of 13 metres then determine the straight-line distance between E and A. (6) [15] 73 marks Total: 150 marks IEB Copyright © 2017