MATHEMATICS PAPER 2
GRADE 12
NATIONAL SENIOR CERTIFICATE
MEMORANDUM
NOVEMBER 2020
NOTE:
GEOMETRY
QUESTION 1
1.1 | a = 9,5 | a = 9,5 | |
1.2 | correct slope going through 2 points: | ||
1.3 | Final exam mark ≈72,22%(calculator) | answer(2) | |
1.4 | r = 0,95 | 🗸 answer(A) (1) | |
1.5 | There is a very strong positive correlation between
| 🗸 strong(1) | |
1.6 | The teacher concludes that the higher the learners' Mathematics | answer (1) | |
[10] |
QUESTION 2
2 018 | 2 175 | 2 182 | 2 215 | 2 254 | 2 263 | 2 267 | 2 271 | 2 293 | 2 323 | 2 334 | 2 346 |
2.1 | July | 🗸 answer |
2.2 | x = 26 941 Answer only: Full marks | 🗸 26 941 |
2.3 | Standard deviation for landings at the King Shaka International airport: | 🗸🗸 answer |
2.4 | (x - σ ; x + σ) = (2 245,08 – 86,30 ; 2 245,08 + 86,30) | 🗸 x - σ |
2.5 | The standard deviation of the number of landings at the Port Elizabeth | 🗸 answer |
[9] |
QUESTION 3
3.1 | mWP = 4 - (-4) = 8 | 🗸 substitution of W and P |
3.2 | mST = ½ (given) | 🗸 (mWP)(mST) |
3.3 | 5y + 2x + 60 = 0 | 🗸 equating
|
5y + 2x + 60 = 0 OR | 🗸 substitution 🗸 adding | |
3.4 | y = -2/5 (- 4)-12 OR 5y + 2(-4) + 60 = 0 OR | 🗸 substitution 🗸 substitution |
3.5 | mSK = - 2/5 | 🗸 mSK |
3.6 | In ΔSRW: OR OR | 🗸⊥h 🗸 ⊥h 🗸SW =8√5 |
[21] |
QUESTION 4
4.1 | x2 + y 2 = r 2 | 🗸 substitution |
4.2 | TM ⊥ TN [tangent ⊥ radius] | 🗸 xT = -11 |
4.3 | O (0 ; 0 ) and M(–3; 4) | 🗸 mOM = - 4/3 |
4.4 | N(–11 ; p) | 🗸subst x = –11 into eq or gradient |
4.5 | B(- 2; 5) | 🗸 2 🗸🗸 k = 6,6 🗸🗸 k = 9,4 |
[19] |
QUESTION 5
5.1 | Period of g = 360° | 🗸 answer (1) | ||
5.2 | Amplitude of f =½ | 🗸 answer (A) (1) | ||
5.3 | f (180°) – g(180°) | 🗸1 (1) | ||
5.4.1 | x = 140,9° | 🗸 x = 140,9° (1) | ||
5.4.2 | 3 sin x + cos x ≥ 1 | 🗸dividing by 2 | ||
[8] |
QUESTION 6
6.1.1 | tanq = - 12/5 or - 22/5 | 🗸answer (1) | |
6.1.2 | (OP)2 = (–5)2 + (12)2 | 🗸 Pythagoras | |
6.1.3 | sin(θ + 90°) = b
| 🗸 sin(θ + 90°) = b 🗸 cos(θ + 90°) = a | |
6.2 | sin 2x. cos(-x) + cos 2x. sin(360° - x) | 🗸 cos(-x) = cos x 🗸 sin(360° - x) = -sin x | |
6.3 | 6 sin2x + 7 cos x - 3 = 0 | 🗸 identity | |
6.4 | x + 1/x = 3cos A OR 3cosA = 2 or 3cosA = -2 | 🗸squaring both sides 🗸 x = ±1 🗸 cos A =2/3 | |
[24] |
QUESTION 7
7.1 | tan 30° = √3r | 🗸🗸 trig ratio |
7.2 | Area of flower garden = π (3r )2 - πr 2 | 🗸 substitution into difference of areas |
7.3 | RS2 = r2 + (3r)2 - 2(r)(3r) cos 2x | 🗸substitution into cosine rule correctly |
7.4 | RS = 10√10 - 6 cos 2(56) | 🗸substitution |
[10] |
QUESTION 8
8.1.1(a) | O2 = 64° | 🗸 S 🗸 R |
8.1.1(b) | M2 = 90° [Line from centre to midpt of chord] OR | 🗸 S 🗸 R 🗸 S 🗸 R |
8.1.2 | PKO + P = 128° [sum of ∠s in ∆] OR | 🗸 S 🗸 S |
8.2 | ||
8.2.1 | F1 = D1 [tan chord theorem] | 🗸 S 🗸 R |
8.2.2 | GC = FB [line || one side of Δ] OR OR | 🗸 S 🗸 R 🗸 S 🗸 R 🗸 S 🗸 R |
QUESTION 9
9.1 | Construction: Draw diameter KS and draw KR | construction |
OR | ||
9.1 | Construction: Draw radii OS and OT | construction |
OR | ||
9.1 | Construction: Draw diameter KS and join K to T. | construction S/R S/R S S/R (5) |
OR | ||
9.1 | Construction: Draw radii OT, OR and OS | construction S/R S/R S S/R (5) |
OR | ||
Construction: Draw radii OT and OS, tangent QT | construction S/R S/R S S/R (5) | |
9.2 | ||
9.2.1(a) | N2 = x [alt ∠s; PR || NQ] | S |
9.2.1(b) | Q2 = x [tan chord theorem] | S |
9.2.2 | MN = MS [QN || PR; Prop Th] | S |
[15] |
QUESTION 10
10.1.1 | DBE = 90° [∠ in semi-circle] OR | S S |
10.1.2 | B3 = D2 [tangent chord th] OR OR | S R (4) S |
10.1.3 | In ∆CDB and ∆CBE OR | S S/R |
10.2.1 | BC = DC [||| Δs] | ratio |
10.2.2 | BC = DB [||| Δs] | BE = 2DB |
TOTAL : 150