MATHEMATICS Grade 12

Transcription

1 Western Cape Education Department Examination Preparation Learning Resource 2016 TRIGONOMETRY General MATHEMATICS Grade 12 Razzia Ebrahim Senior Curriculum Planner for Mathematics / Website: grade-12?itemid=-1 Website:

2 Index November Paper June Paper Feb-March Paper November Paper June Paper Feb-March Paper November Paper 2 Page Exemplar Paper 2 9 Page 2

3 Mathematics P2/Trigonometry General 3 QUESTION 5 DBE/November Given: sin16 p Determine the following in terms of p, without using a calculator sin196 (2) cos 16 (2) 5.2 Given: cos(a B) cosacosb sinasinb Use the formula for cos(a B) to derive a formula for sin(a B) 5.3 Simplify 2 1 cos 2A cos( A).cos(90 A) completely, given that 0 A 90. (5) 5.4 Given: 3 cos 2B and 0 B 90 5 Determine, without using a calculator, the value of EACH of the following in its simplest form: cos B sin B (2) cos (B + 45 ) (4) [21] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 3

4 Mathematics P2/Trigonometry General 4 DBE/2016 QUESTION In the diagram PR TS in obtuse triangle PTS. PT = 5 ; TR = 2; PR = 1; PS = 10 and RS = 3 P 1 T R 3 S Write down the value of: (a) sin T (1) (b) cos S (1) Calculate, WITHOUT using a calculator, the value of cos(t S ) (5) Determine the value of: 1 tan 2 (180 ) cos(360 ). sin(90 ) 5.3 If sin x cos x (6) 3, calculate the value of sin 2 x WITHOUT using a calculator. 4 Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 4 (5) [18]

5 Mathematics P2/Trigonometry General 5 QUESTION 5 DBE/Feb.-Mar P (-.fl; 3) and S(a ; b) are points on the Cartesian plane, as shown in the diagram below. POR = POS = 0 and OS = 6. P(-..fi; 3 y S(a; b) Determine, WITHOUT using a calculator, the value of: tan sin(-0) a (1) (4) Simplify 4sinxcosx to a single trigonometric ratio. 2sin 2 x sinl5 cosl5 Hence, calculate the value of WITHOUT using a 2 sin calculator. (Leave your answer in simplest surd form.) (2) [13] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 5

6 Mathematics P2/Trigonometry General 6 QUESTION 5 DBE/November Given that sin 23 = k, determine, in its simplest form, the value of each of the following in terms of k, WITHOUT using a calculator: sin 203 (2) cos tan( 23 ) (2) 5.2 Simplify the following expression to a single trigonometric function: 4cos( x).cos(90 + x) sin(30 x).cos x + cos(30 x).sin x (6) 5.3 Determine the general solution of cos 2x 7cos x 3 = 0. (6) Given that sin θ =, calculate the numerical value of sin 3θ, WITHOUT using 3 a calculator. (5) [24] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 6

7 Mathematics P2/Trigonometry General 7 QUESTION 5 DBE/ Given that cos p = -Js, where 180 < p < 360. Determine, with the aid of a sketch and without using a calculator, the value of sin p. (5) 5.2 Determine the value of the following expression: tan(l 80 - x ). sin(x - 90 ) 4sin(360 + x) (6) 5.3 If sin A = p and cos A = q: Write tan A in terms of p and q Simplify p 4 -q 4 to a single trigonometric ratio (1) (4) 5.4 cos 0 cos 20 Consider the identity: -- - = tan 0 sin 0 sin 0. cos Prove the identity. (5) For which value(s) of 0 in the interval 0 < 0 < 180 will the identity be undefined? 5.5 Determine the general solution of 2 sin 2x + 3 sin x = 0 (2) (6) [29) Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 7

8 Mathematics P2/Trigonometry General 8 QUESTION 5 DBE/Feb.-Mar If x = 3 sin 0 and y = 3 cos 0, determine the value of x 2 + y Simplify to a single term: sin(54<j'- x).sin(-x)-cos(l 8<J'- x).sin(90 + x) (6) 5.3 In the diagram below, T(x ; p) is a point in the third quadrant and it is given that. p sma=. -vl + p 2 T(x ;p) Show that x = Write cos (l 8<J' +a) in terms of p in its simplest form. (2) Show that cos 2a can be written as 1-p 2 I+ p For which value(s) of x will interval 0 :S x :S 180? 2 tanx-sin2x 2sin 2 x be undefined in the tanx-sin2x Prove the identity: -----= tanx 2sin 2 x (6) [26) Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 8

9 Mathematics P2/Trigonometry General 9 QUESTION 6 DBE/November Prove the identity: cos 2 ( 180 x) tan(x 180 )sin(720 x)cos x cos 2x (5) 6.2 Use cos( ) cos cos sin sin to derive the formula for sin( ). 6.3 If sin 76 = x and cos 76 = y, show that 2 2 x y = sin 62. (4) [12] NSS Graad 12 Model Memorandum DBE/2014 QUESTION Given that sin α = 5 4 and 90 < α < 270. WITHOUT using a calculator, determine the value of each of the following in its simplest form: sin ( α) (2) cos α (2) sin (α 45 ) 8sin(180 x)cos( x 360 ) 5.2 Consider the identity: = 4 tan 2x 2 2 sin x sin (90 + x) Prove the identity. (6) For which value(s) of x in the interval 0 < x < 180 will the identity be undefined? (2) 5.3 Determine the general solution of cos 2θ + 4sin θ 5sin θ 4 = 0. (7) [22] 2 Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 9

10 Western Cape Education Department Examination Preparation Learning Resource 2016 TRIGONOMETRY Graphs MATHEMATICS Grade 12 Razzia Ebrahim Senior Curriculum Planner for Mathematics / Website: grade-12?itemid=-1 Website: Page 10

11 Index November Paper June Paper Feb-March Paper November Paper June Paper 2 Page Feb-March Paper November Paper Exemplar Paper Page 11

12 Mathematics P2/Trigonometry Graphs 3 QUESTION 6 In the diagram the graph of DBE/November 2016 f ( x) 2sin 2x is drawn for the interval x [ 180 ; 180 ]. y 2 1 f x On the system of axes on which f is drawn in the ANSWER BOOK, draw the graph of g( x) cos 2x for x [ 180 ; 180 ]. Clearly show all intercepts with the axes, the coordinates of the turning points and end points of the graph. 6.2 Write down the maximum value of f ( x) 3. (2) 6.3 Determine the general solution of f ( x) g( x). (4) 6.4 Hence, determine the values of x for which f ( x) g( x) in the interval x [ 180 ; 0 ]. [12] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page Please 12turn over

13 Mathematics P2/Trigonometry Graphs 4 DBE/2016 QUESTION Determine the general solution of 4 sin x 2 cos 2 x The graph of g ( x) cos 2 x for x [ 180 ; 180 ] is drawn below. (6) y 2 1 g 180 o 90 o O 90o x 180o Draw the graph of f ( x) 2 sin x 1 for x [ 180 ; 180 ] on the set of axes provided in the ANSWER BOOK. Write down the values of x for which g is strictly decreasing in the interval x [ 180 ; 0 ] (2) Write down the value(s) of x for which x [ 180 ; 180 ] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED f ( x 30 ) g ( x 30 ) 0 for (2) [13] Please Page 13turn over

14 Mathematics P2/Trigonometry Graphs 5 QUESTION6 DBE/Feb.-Mar Given the equation: sin(x + 60 ) + 2cos x = Show that the equation can be rewritten as tan x = J?,. Determine the solutions of the equation sin(x + 60 ) + 2cos x = 0 in the interval -180 :Sx :S 180. (4) 6.3 In the diagram below, the graph of f(x) =-2 cos x is drawn for -120 :Sx :S y I Draw the graph of g(x) = sin(x + 60 ) for -120 :S x :S 240 on the grid provided in the ANSWER BOOK Determine the values of x in the interval -120 :S x :S 240 sin(x + 60 ) + 2cos x > 0. for which [13) Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 14

15 Mathematics P2/Trigonometry Graphs 6 QUESTION 6 In the diagram below, the graphs of ( and g x) = sin( x + p) f x) = cos x + q DBE/November 2015 ( are drawn on the same system of axes for 240 x 240. The graphs intersect at 1 0 ; 2, ( 120 ; 1) and (240 ; 1). 1 y 1 2 g x f 6.1 Determine the values of p and q. (4) 6.2 Determine the values of x in the interval 240 x 240 for which f (x) > g(x). (2) 6.3 Describe a transformation that the graph of g has to undergo to form the graph of h, where h( x) = cos x. (2) [8] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 15 Please turn over

16 Mathematics P2/Trigonometry Graphs 7 QUESTION6 In the diagram below the graphs of f (x) = sin bx and g(x) = -cos x -90 ::;; x::;; 90. Use the diagram to answer the following questions. DBE/2015 are drawn for 90 I Write down the period of.f Determine the value of b. (1) (1) 6.3 The general solutions of the equation sin bx = - cos x are x = 67,5 + k.90 or x = 135 +k.180 where kez. Determine the x-values of the points of intersection of f and g for the given domain. 6.4 Write down the values of x for which sin bx + cos x < 0 for the given domain. (4) [9] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page Please 16turn over

17 Mathematics P2/Trigonometry Graphs 8 QUESTION 7 DBE/November 2014 In the diagram below, the graph of f (x) = sin x + 1 is drawn for 90 x y f x Write down the range of f. (2) 7.2 Show that sin x 1 cos 2x can be rewritten as ( 2sin x 1)sin x 0. (2) 7.3 Hence, or otherwise, determine the general solution of sin x 1 cos 2x. (4) 7.4 Use the grid on DIAGRAM SHEET 2 to draw the graph of g( x) cos 2x for 90 x Determine the value(s) of x for which f(x + 30 ) = g(x + 30 ) in the interval 90 x Consider the following geometric series: cos 2x + 4 cos 2 2x +... Use the graph of g to determine the value(s) of x in the interval 0 x 90 for which this series will converge. (5) [19] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 17

18 Mathematics P2/Trigonometry Graphs 9 QUESTION 6 In the diagram below, the graphs of f (x) = tan bx and g(x) = cos (x 30 ) are drawn on the same system of axes for 180 x 180. The point P(90 ; 1) lies on f. Use the diagram to answer the following questions. y f A P(90 ; 1) 180 g x 6.1 Determine the value of b. (1) 6.2 Write down the coordinates of A, a turning point of g. (2) 6.3 Write down the equation of the asymptote(s) of y = tan b(x + 20 ) for x [ 180 ; 180 ]. (1) 6.4 Determine the range of h if h(x) = 2g(x) + 1. (2) [6] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 18

19 Western Cape Education Department Examination Preparation Learning Resource 2016 TRIGONOMETRY Formulae MATHEMATICS Grade 12 Razzia Ebrahim Senior Curriculum Planner for Mathematics / Website: grade-12?itemid=-1 Website: Page 19

20 Index November Paper June Paper Feb-March Paper November Paper June Paper Feb-March Paper November Paper 2 Page Exemplar Paper 2 11 Page 20

21 Mathematics P2/Trigonometry Formulae 3 QUESTION 7 DBE/November 2016 E is the apex of a pyramid having a square base ABCD. O is the centre of the base. EBˆ A, AB = 3 m and EO, the perpendicular height of the pyramid, is x. E D x C O A 3 B 7.1 Calculate the length of OB. 7.2 Show that cos 2 x (5) 7.3 If the volume of the pyramid is 15 m 3, calculate the value of. (4) [12] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 21

22 Mathematics P2/Trigonometry 4 DBE/2016 QUESTION 7 From point A an observer spots two boats, B and C, at anchor. The angle of depression of boat B from A is. D is a point directly below A and is on the same horizontal plane as B and C. BD = 64 m, AB = 81 m and AC = 87 m. A D B C 7.1 Calculate the size of to the nearest degree. 7.2 If it is given that BA C 82,6, calculate BC, the distance between the boats. 7.3 If BD C 110, calculate the size of DC B. [9] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Please Page 22turn over

23 Mathematics P2/Trigonometry Formulae 5 QUESTION 7 DBE/Feb.-Mar In the diagram below, PQR is drawn with PQ = 20-4x, RQ = x and Q = 60. Q x X R Show that the area of PQR = s.fix -,J3x Determine the value of x for which the area of PQR will be a maximum Calculate the length of PR if the area of PQR is a maximum. (2) 7.2 In the diagram below, BC is a pole anchored by two cables at A and D. A, D and C are in the same horizontal plane. The height of the pole is h and the angle of elevation from A to the top of the pole, B, is /J. ABO= 2/J and BA= BO. A C 0 Determine the distance AD between the two anchors in terms of h. (7) [15] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 23

24 Mathematics P2/Trigonometry Formulae 6 QUESTION 7 A corner of a rectangular block of wood is cut off and shown in the diagram below. The inclined plane, that is, ACD, is an isosceles triangle having A Dˆ C = AĈD = θ. 1 Also A ĈB = θ, AC = x + 3 and CD = 2x. 2 A DBE/November 2015 x + 3 θ D B 1 θ 2 θ 2x C 7.1 Determine an expression for CÂD in terms of θ. (1) 7.2 Prove that x cosθ =. (4) x If it is given that x = 2, calculate AB, the height of the piece of wood. (5) [10] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 24

25 Mathematics P2/Trigonometry Formulae 7 QUESTION 7 DBE/2015 Triangle PQS forms a certain area of a park. R is a point on PS and QR divides the area of the park into two triangular parts, as shown below, for a festive event. PQ = PR = x units, RS = 3x units and RQ = J3 x units. 2 P,_ -- x : R ;- ----= ::-::;;;- S 3x Q 7.1 Calculate the size of P. 7.2 Hence, calculate the area of triangle QRS in terms of x in its simplest form. (4) (5) [9] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 25

26 Mathematics P2/Trigonometry Formulae 8 QUESTION6 DBE/Feb.-Mar In the figure, points K, A and F lie in the same horizontal plane and TA represents A A A a vertical tower. ATK = x, KAF =90 + x and KFA = 2x where 0 < x < 30. TK = 2 units. T K F Express AK in terms of sin x. Calculate the numerical value of KF. (2) (5) Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 26

27 Mathematics P2/Trigonometry Formulae 9 DBE/Feb.-Mar In the diagram below, a circle with centre O passes through A, B and C. BC = AC = 15 units. BO and OC are joined. OB = 10 units and BOC= x. Calculate: The size of x The size of ACB The area of ABC (4) (2) [16] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 27

28 Mathematics P2/Trigonometry Formulae 10 QUESTION 5 DBE/November 2014 In the figure below, ACP and ADP are triangles with Ĉ = 90, CP = 4 3, AP = 8 and DP = 4. PA bisects D Pˆ C. Let CÂP x and DÂP y. C 4 3 A x y 8 P Show, by calculation, that x = 60. (2) 5.2 Calculate the length of AD. (4) 5.3 Determine y. [9] D Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 28

29 Mathematics P2/Trigonometry Formulae 11 QUESTION Prove that in any acute-angled ABC, sina sinb =. (5) a b 7.2 The framework for a construction consists of a cyclic quadrilateral PQRS in the horizontal plane and a vertical post TP as shown in the figure. From Q the angle of elevation of T is y. PQ = PS = k units, TP = 3 units and S Rˆ Q = 2x. T 3 P y Q k S 2x R Show, giving reasons, that P ŜQ = x. (2) Prove that SQ = 2k cos x. (4) Hence, prove that SQ = 6cos x tan y. (2) [13] Compiled by R.Ebrahim Senior Curriculum Planner FET Mathematics WCED Page 29