TECHNICAL MATHEMATICS PAPER 2
GRADE 12
NATIONAL SENIOR CERTIFICATE
MEMORANDUM
JUNE 2018

NOTE:

  • Continuous accuracy (CA) applies in ALL aspects of the marking guideline.
  • After two mistakes, do not apply CA marking.
  • Assuming values/answers in order to solve a problem is unacceptable.
Symbol Explanation 
 M Method 
 MA Method with accuracy 
 A Accuracy 
 CA Consistent accuracy 
 S Simplification or Statement 
 R Reason
 SR Statement and correct reason


QUESTION 1

 1

1.1

BC =√( x2 - x1)2 + (y2 - y1)2
= √(8-0) 2 + (0+6) 2 
=√100
= 10

MA formula ✓

substitution ✓

CA Answer ✓

(3)

1.2

 2

A x-coordinate✓ 

A y-coordinate✓

(2)

1.3

mBC = y2 - y1
           x2 - x1
0 + 6
    8 - 0

    8

    4
= 0,75

MA formula and substitution ✓

CA Simplification ✓

(2)

1.4

y - y1 = m ( x - x1 )
y - 2 = 0, 75( x - 2)
y = 0, 75x + 0, 5

M Correct formula✓

A Correct substitution pt D or E ✓

CA Simplification ✓

CA Standard form ✓

(4)

1.5  inclination of DE = inclination of BC (lines; same gradient)

mDEmBC
tan incl DE = 0, 75
incl DE = 36,87°
mAE4 + 6- 5
          -4 - 0      2
tan incl AE =- 5
                      2
incl AE = 180° - 68,198...°
= 111,8°

AED = 111,8° - 36,87°
= 74, 93°

M mDE = mBC ✓

A tan incl DE = 0, 75 ✓

CA incl DE = 36,87° ✓

MA mAE =- 5
                   2

CA incl AE = 111,8°✓

CA  AED = 74,93°✓

(6)

   

[17]

 

QUESTION 2

3

2.1.1

r2 = x2 + y2
= (-5)2  + (-12)2
= 169
∴ Equation of circle: x2 + y2 = 169

M Correct formula✓

A Correct substitution✓

CA Value of r2

(3)

2.1.2

mradius = 0 +1212
                0 + 5     5
mtangent =- 5 ≈ -0, 42
                12
Equation of tangent:
y - y1 = m ( x - x1)
y +12 = -0, 42( x + 5)
y = -0, 42x -14,1

OR

mradius = 0 +1212
                0 + 5     5
mtangent =- 5 
                12
y y1 = m ( x x1 )
y +12 = - 5 ( x + 5)
              12
y +12 = - 5 x - 25
              12     12
y = - 5 x - 169
         12    12

OR

x1 x + y1 y = r 2 
-5x -12 y = 169
y = - 5 x - 169
       12      12

MA Gradient of radius✓

CA Gradient of tangent✓

A Subst. P into equation✓

CA Equation of line✓

 

CA Gradient of tangent✓

MA Gradient of radius✓

CA Gradient of tangent✓

A Subst. P into equation✓

 

M Correct formula✓

A Correct substitution of P✓

A Correct substitution of grad.✓

CA Equation of line✓

(4)

2.2

4x2 + 9 y2 = 36
 x 2 +  2 = 1
 9       4

 x 2 + 2 =1 
32    22  

 

M Rewrite the equation RHS = 1✓

M Rewrite into a2 & b2

CA x-intercepts✓

CA y-intercepts✓

CA shape – clearly showing the horizontal major axis✓

(5)

4
  [12]

 

QUESTION 3

3.1

 5

3.1.1

13sinθ = 12
sinθ = 12 
          13
x = -√132 -122 (Pyth)
x = -5
y = 12
P(-5;12)

M sin θ the subject✓

M Pythagoras✓

A x-value✓

A y-value✓

(4)

3.1.2

tanθ + secθ = 12 + 13
                       -5     -5
= 25 
   -5
= -5

CA correct value: tan✓

CA correct value: sec✓

CA answer✓

(3)

3.1.3

sinθ = 12 
           13
Ref ∠ = sin-1(12/13 ) = 67, 38...°
θ = 180° - 67, 38...°
θ = 112, 6°

M 180° -✓

CA 112,6°✓

(2)

3.2

 6

A - tanq✓

A cos θ✓

A  (-cosq )2

A  (-sinq )2

A sinθ
   cosθ

A cos2 θ +sin2 θ =1✓

CA -sinθ✓

(7)

3.3

RHS =  2  
          sin a
LHS = 1+ cos a  +   sin a  
              sin a        1+ cos a
=  (1+ cos a )2  + sin2
        sin a(1+ cos a)
= 1+ 2 cos a + cos2 a + sin2 a
         sin a (1+ cos a )
=   1+ 2 cosa +1   
    sin a (1+ cosa )
=    2 + 2 cos a    
   sin a (1+ cos a )
   2(1+ cos a)    
    sin a (1+ cosa )
  2  
  sin a
= RHS

A RHS✓

A denominator✓

A numerator✓

A cos2 a +sin2 a =1✓

CA expansion✓

CA factorising✓

(6)

     [22]

 

QUESTION 4

7

4.1

sinθ = 9, 48 = 0, 606...
          15, 64
θ = 37, 3°

A trig ratio✓

CA value for θ ✓

(2)

4.2

Area Δ PSR = ½ PS´SQ sin PSˆQ
= 0, 5´ 4, 95´15, 64´sin 52, 69°
= 30, 79 cm2

A area-rule✓

CA value for PSˆQ✓

A correct substitution✓

CA Area of ∆DEF✓

(4)

4.3

PSˆQ = 90°- 37,31° = 52, 69°
PQ2 = PS 2 + SQ2 - 2PS ´ SQ cos PSˆQ
= 4, 952 +15, 642 - 2´ 4, 95´15, 64 cos 52, 69°
= 175, 261...
PQ = √175, 261...
» 13, 24 m2

A cos-rule✓

A correct substitution✓

CA simplification✓

CA value of✓

(5)

 

 

 [11]

 

QUESTION 5

5.1.

 8

A x-int’s 120° and 300°✓

A TP (30°;1)✓

A TP (210°;-1)✓

A shape✓

(4)

5.2.1

Amplitude of f = 2

amplitude = 2

(1)

5.2.2

Range g: –1 ≤ y ≤ 1

A y- values✓

CA interval✓

(2)

5.2.3

x = 90°

CA ✓ (1)

5.2.4

f (x) ≤  g(x) ⇔ x Î[210°;360°]

OR

210° ≤  x £≤ 360°

CA x = 210°✓

CA x = 360°✓

A notation✓

(3)

     [11]

 

QUESTION 6

6.1

Proportionally(1)

6.2

 9
 

Let QS = x
SC = 4 – x
CS = CR (line || to one side of D)
SA     RB
4 - x = 1 
x + 2   3
12 - 3x = x + 2
10 = 4x
x = 2,5
∴ QS = 2,5 units

S SC = 4 –

S

S SA = x + 2 ✓

A Setup equation ✓

CA Simplify equation✓

CA value✓

(7)

 

     [8]

 

QUESTION 7

7.1

 10

7.1.1

AB = 8,36 cm (sides opp = ∠ s)
BD = 5,91 cm

S ✓✓

(3)

7.1.2

AB 8, 36 ≈ 1, 41
BD    5, 91

BC8, 36 ≈ 1, 41
DC    5, 91

AC11,82 ≈ 1, 41
BC     8, 36

(3)

7.1.3

triangles are similar

S similar triangles ✓

(1)

7.2

 11

7.2.1(a)

Rˆ3  = Tˆ2 = 56° (∠s in same segment)

S R(2) ✓✓

7.2.1(b) Rˆ = T1 = 56° (tan-chord) S ✓✓ (2)
7.2.2

Aˆ = Mˆ   (∠s in same segment)
Aˆ = Rˆ1   (tan-chord)

(2)

7.2.3

APPR       (Δ s /// )
MP    PT

8, 29      11,11     
 MP     12, 01- 8, 29

MP = 8, 29 x 3, 72
               11,11
= 2, 78 cm

S PT = 12,01 – 8,29 = 3,72 ✓

S value of ✓

(5)

    [18]

  

QUESTION 8

8.1

 12
 

PTˆR = 90°        (line from centre to midpt of chord)
TR2 = PR2 - PT 2          (Pythagoras)

= 9, 472 - 8, 432

= 18, 616

TR = 4, 31...

WR ≈ 8, 63 units

S Pythagoras ✓

A Simplification✓

CA Value of TR✓

CA Value of WR✓

(6)

8.2

 13
 

ABO = 40°    (radii; equal ∠ s opp equal sides)
AOB = 100°   (int ∠s of D)
D = 50°    (∠ at centre = 2 ∠ at circumf.)
x = 130° (opp ∠s of cyclic quad)

(6)

     [12]

 

QUESTION 9

9.1.1

108, 5° = 108, 5° x   π  
                              180°
= 217 π
   360
= 1,89 radians

A Multiply with factor✓

CA Answer✓

(2)

9.1.2

Radius = 10,84 = 5, 42 units 
                  2

A Answer✓

(1)

9.1.3

s = rθ
d = 5, 42 ´1,89
= 10, 24 units

A correct✓

CA ✓ Substitution

CA answer ✓

(3)

9.1.4

Area =2 θ
             2
5, 42 x 1,89
            2
= 27,76 units2

A Correct formula✓

CA Substitution✓

CA answer✓

(3)

9.2

4h2 - 4dh + x2 = 0
d =    x 2 + h
       4h
= 8, 76  + 3,15
  4 x 3,15
= 9, 24 units

A Correct formula✓

A Making d the subject✓

A Substitution✓

CA answer✓

(4)

 9.3   14
   15

A Correct formula✓

A Convert to cm ✓

A Substitution✓

CA 109,8✓

CA 658,8✓

(5)

    18]

 

QUESTION 10

10.1.1

n = 15 rev/s
ω = 2πn
= 2p (15)
= 30π
= 94, 25 rad/s

A Correct formula ✓

Substitution✓

CA value of✓

(3)

10.1.2

d = 570mm = 0, 57m
υ = πDn
= π(0, 57)(15)
= 26,86 m/s

A Convert diameter to metre✓

A Correct formula✓

A Substitution✓

CA value of v✓

(4) 

10.1.3

s=vt
= 26,86...x(2 x 60)
= 3223 m

A Correct formula✓

A Multiply t = 2, with 60✓

CA value of s✓

CA rounded answer✓

(4)

10.1.4

θ = ωt
= (30π )(0, 3)
=9π rad

A Correct formula✓

Substitution✓

CA value of θ✓

(3)

10.2

Vol of cylinder = πr2h
16

A Formula of cylinder ✓

A Divide diameter by 2✓

A Substitution✓

CA Vol of cylinder✓

A Formula of hemisphere✓

Substitution ✓

CA Vol of hemisphere✓

CA Adding the volumes✓

(7)

   

[21]

TOTAL;150

Last modified on Thursday, 12 August 2021 13:46