MATHEMATICS
PAPER 2
GRADE 12 
NSC EXAMS PAST PAPERS AND MEMOS JUNE 2019

MEMORANDUM 

QUESTION 1

1.1 

Mean = 48 

✔ 48  (1)

1.2 

SD/SA = 22,08
Penalty of 1 mark for incorrect rounding  

✔✔22,08  (2)

1.3 

Girls performed better.  
The girls’ mean percentage is bigger than that of boys and the girls  standard deviation is smaller than that of boys  

✔Girls 
✔Reason (2)

1.4 

51 – 48 = 3  
∴each boy’s percentage must be increased by 3.  

✔3  (1)

1.5 

Boys’ standard deviation will remain the same  

✔remain the same   (1)

   

[7]

QUESTION 2

2.1 

Ages (in years)    Frequency  Cumulative Frequency  
18 ≤ x < 28  4  4
28 ≤ x < 38  10  14
38 ≤ x < 48  14  28
48 ≤ x < 58  17  45
58 ≤ x < 68  12  57
68 ≤ x < 78  3  60
 

✔frequency  
✔cumulative  frequency   (2)

2.2 

22 jygatfaygd

✔grounding at (0 ; 18)  
✔upper limits  
✔shape  (3)

2.3 

48 ≤ x < 58 

✔answer  (1)

2.4 

60 – 49 = 11 senior citizens 

✔49  
✔answer(2)

2.5 

Q1 = 39  
Q2 = 50  
Q3 = 58 

✔value of  Q1 
✔value of Q2
✔value of  Q3  (3)

2.6 

2.6 kjajgujgdauygd

✔minimum and  maximum  
✔ box (2)

   

[13]

QUESTION 3
3 kgauguygda

3.1.1 

3.1.1 jkyguafuyfgda

✔substitution 
✔answer  (2)

3.1.2 

mKM = y2 - y1
            x2 - x1
 = -4 - 7
     7 - 0
= - 11
      7 

✔substitution
✔gradient of KM (2)

3.1.3 

mLM = y2 - y1
            x2 - x1
 = -4 - 2
     7 - 10
= 2
tan α =  2 
∴ α =  63,43º

✔gradient of LM 
✔ tan α =  2 
✔value of α  (3)

3.1.4 

tanθ = - 11
              7 
Ref ∠ = 57,53º
∴θ = 122,47º
LMK = 122,47º -  63,43º
 = 59,04º

✔tanθ = - 11
                 7 
✔reference angle 
✔value of θ
✔value of LMK∧ (4)

3.2 

3.2 KJGAJFJHDGA

✔ y = 2x + 7
✔ y = -x - 1
           2   2
✔value of x
✔value of y 

OR 

✔mKL = -5
              10 
✔mNM = -5
               10
✔value of x
✔value of y 

OR
✔Midpoint of KM  = 3.2 B KJAJGUYGDA
✔ Midpoint of LN = 3.2 B KJAJGUYGDA
✔value of x  
✔value of y (4)

3.3 

mLM × mMN = 2 × (-½)
= -1
∴LMN = 90º

OR LMN is a right angle

✔product of gradients
✔conclusion (2)

3.4 

3.4 mhgajfuyda
LMN = 90º and LMK = 59,04º
∴KMN = 90º - 56,04º = 30,96º
Area of KMN = ½  × √170  ×  5√5  ×  sin30,96º
=37,50 square units

✔KL  = NM = 5√5
✔KM  = √170  
✔LMN = 90º and LMK = 59,04º
✔KMN = 30,96º
✔Area of KMN Δ  (5)

   

[22]

QUESTION 4
4 nfahfhdfhad

4.1 

M (2 ; 4) 

✔value of x 
✔value of y  (2)

4.2 

r2 = (5 - 2)2 + (0 - 4)2 
= 25
∴ (x - 2)2 + (y - 4)2 = 25

✔ (x - 2)2
✔ (y - 4)2
✔25     (3)

4.3 

mGH = 8 - 0
          -1 - 5
= - 8 = - 4
     6       3
mtan =  3/4
y - 8 = 3/4(x - 1)
∴y = 3/4x + 35/4

✔mGH 
✔mtan 
✔substitution 
✔equation  (4)

4.4 

At J, y = 0  
(x - 2)2 + (0 - 4)2 = =25
(x - 2)2 = 9
x - 2 = ±3
x = 5 or x = -1
∴ J (-1;0) 

✔ y = 0  
✔substitution 
✔ x = – 1   (3)

4.5 

HJG is a right angled triangle (8,6  and 10).  So the rotation of J around M will complete a rectangle Hence, j ((-1 + 6; 0 + 8)) = J'(5;8)

✔value of x 
✔value of y  (2)

4.6 

x2 + y2 - 12x - 2y + 17 = 0
x2 - 12x + y2 - 2y = -17
x2 - 12x + 36 + y2 - 2y + 1 = -17 + 36 + 1
(x - 6)2 + (y - 1)2 = 20
Distance between the centres:  
4.6 jkygaufhdfa
∴ the centre lies on the original circle

✔completing the square
✔factorisation: x
✔factorisation: y 
✔distance formula 
✔conclusion  (5)

   

[19]

QUESTION 5

5.1.1 

5.1.1 hjtfahytfhfad

5.1.1. b jhgvjuhgyugayud  (2)

5.1.2 

sin84º = sin2 × 42º
= 2sin42ºcos42º
5.1.2 jgaytfytdaf

✔double angle
✔expansion
✔substitution   (3)

5.1.3 

sin3º = sin(45º - 42º
= sin45ºcos42º - -cos45ºsin42º
5.1.3 jgathfhgfda

✔3° = 45° – 42°  
✔expansion
✔substitution
✔substitution  (4)

5.2 

sin(x - 450º).tan(180º + x).sin(90º - x)
                      cos(-x)
-cos x.tan x.cos x
         cos x
-cos x.sin x
    cos x
-sin x

✔− cos x 
✔ tan x 
✔cos x 
✔cos x 
sin x
    cos x
✔answer   (6)

5.3.1 

cos (A + B) = cos A cos B - sin A sin B 

✔expansion  (1)

5.3.2 

5.3.2 jkgatyfydta

✔compound angle identity  
✔cos double angle identity  
✔sin double angle identity  
✔ (1 - cos2α)  (4)

Related Items

5.4 

5.4 jvyhafhgad

5.4 b jhygjuygjyad
✔ cos2 θ = cos2θ -  sin2θ 
✔substitution
✔standard form  
✔values of p

OR

✔ 2cos2θ − 1 
✔✔substitution 
✔standard form
✔values of p

OR

5.4 b jhygjuygjyad
✔ 1 - 2sin2θ 
✔substitution  
✔standard form  
✔values of p  (5)

   

[25]

QUESTION 6

6.1 

y∈[-1;1] 
OR
-1 ≤ y ≤ 1

✔answer (1)

6.2 

6.2 hbgjyguyjgad

g:  
✔asymptotes at -90° and 90°  
✔x-intercepts  
✔shape  (3)

6.3 

180° 

✔180°  (1)

6.4 

x = – 45° 

✔– 45°  (1)

6.5 

x∈[45º ; 90º) 
OR
45º ≤ x < 90º

✔critical values  
✔notation (2)

6.6 

h(x) =sin (x – 45°) + 1 

✔h(x) =sin (x – 45°) + 1  

(1)

   

[9]

QUESTION 7  
7 bjhagjgdjab

7.1 

InΔ KLN : 
tan w =   h   
              LN
LN =    h    
        tan w

✔ LN =    h     (1)
            tan w

7.2 

7.2 jkgaufdagd

✔correct sine rule  
✔substitution  
✔isolating LM  
✔answer  (4)

7.3 

LM = h sin(y + z)   and 
         tan w sin z
h = 38m,   w = 21º,  y = 52º   and z = 59
∴LM = 38.sin(52º + 59º)
            tan21º sin59º
= 107,82m

✔substitution  
✔answer (2)

   

[7]

QUESTION 8
8 jhgjagjgadjg

8.1 

the centre of a circle  

✔answer (1)

8.2.1 

AC = 10 cm (line from centre ⊥ chord)   

✔length of AC  
✔Reason  (2)

8.2.2 

(x + 5)2 = 102 + x2
x2 + 10x + 25 = 100 + x2
10x = 75
 ∴ x = 7,5cm
∴radius = 7,5cm +5cm 
= 12,5cm 

✔radius = (x + 5)  
✔applying Pythagoras theorem
✔value of x
✔length of radius (4)

   

[7]

QUESTION 9
9 jhgjaghdga

9.1 

interior opposite angle 

✔answer (1) 

9.2.1 

R2 = Q2 = 41° (∠s in the same seg)
P4 = Q1 = 41° (tan-chord theorem)
T1 = P4 = 41° (∠s opp. = sides)/(∠e teenoor gelyke sye)  

OR

T1 = R2 = 41° (tan – chord theorem)/(raaklyn-koord stelling) 

✔Statement  
✔Reason   
✔Statement 
✔Reason  
✔Statement 
✔Reason (6)

9.2.2(a) 

T2 + 34° = 78°   (tan - chord theorem )
∴T2 = 44°

✔Statement 
✔Reason (2)

9.2.2(b) 

41° + Q2 + 44° + 34° = 180°   ( opp. ∠ s of a cyclic quad.) 
∴Q2 = 61°

✔Statement 
✔Reason (2)

9.2.2(c) 

T4 = 41°  + 61°     ( ext. ∠s of a cyclic quad.) 
∴T4 = 102°  
OR
T4 + 44°  + 34°  = 180°   (int.∠s of a Δ)

✔Statement  
✔Reason 

OR

✔Statement 
✔Reason (2)

9.2.2(d) 

W + 41°+ 41° = 180° ( int .∠s of a Δ)
∴ ܹW = 98° 

✔Statement
✔ Reason (2)

9.2.3(a) 

Q2 =  61º      and   T2 =  44º 
∴ Q2  ≠  T2
∴  QR is not parallel to PT (alt. ∠s are not equal) 

✔Q2 ≠  T2
✔alt. ∠s are not equal  (2)

9.2.3(b) 

R2 + W =  41º +  98º
= 139º ≠ 180º 
∴ PRTW is not a cyclicquad. (Opp. ∠s are not supp.) 

✔R2 +W ≠ 180º
✔ PRTWis not a cyclicquad. (2)

9.2.3(c) 

R1 = T2 = 44°(∠s in same seg) 
R1 + R2 = 44° + 41°  
               = 95° ≠ 90°  
∴ TQ is not a diameter (∠subt. by TQ is not a right angle) 

✔R1 + R2 ≠  90º
✔TQ is not a diameter (2)

 

[21]

QUESTION 10

10.1 

10.1 KHBGAJGVCGV
Construction: Draw heights h and l on KR and KS  respectively. Join LS and MR  
Proof:
10.12 JHBVAHUGVDHGAV
But: area of ΔLRS =  area of ΔMSR
Area of ΔKRS = Area of ΔKRS    
Area of ΔLRS     Area of ΔMSR 
KR = KS
   RL    SM

✔construction 
✔ratio of areas   
✔ratio of areas  
✔same base and same height  
Area of ΔKRS = Area of ΔKRS    (5)
    Area of ΔLRS     Area of ΔMSR 

 

 

10.2 KHBAGUDYGAUYD

10.2.1 

AB = 5 units 

✔5  (1)

10.2.2(a) 

C is common 
CBA = CFB (both =90°) 
CAB = CBF (sum of ∠s of Δ)
∴ ΔCBA|||ΔCFB (∠, ∠, ∠)

✔Statement /  Reason
✔Statement / Reason
✔Reason  (3)

10.2.2(b) 

CB = CA  (|||Δs)
CF    CB 
CB2 = CF.CA
∴ CF = CB2
            CA

✔proportion
✔reason
✔ CB2 = CF.CA (3)

10.2.3 

 CF = CB2
          CA
 CF = (12)2
           13
≈ 11units

✔substitution g 
✔length of CF   (2)

10.2.4 

AF = 13 – 11 = 2 unit

✔length of AF (1)

10.2.5 

CB  =  CA = (prop. theorem ; DF||BA )
BD      AF 
12 = 13
BD    2 
∴ BD = 24
            13

CF = CB (prop. theorem ; DF ||BA )
FE    BD 
11 = 12
FE   24 
        13 
∴FE = 22 units
          13 

✔proportion  
✔reason 
✔length of BD  
✔proportion 
✔length of FE (5)

   

[20]

     
   

TOTAL: 150

Last modified on Tuesday, 05 October 2021 12:26