MATHEMATICS
PAPER ONE(P1)
GRADE 12
EXAM PAPERS AND MEMOS
SEPTEMBER 2016
NOTE:
QUESTION 1 | ||||
1.1.1 | 𝑥2 − 4𝑥−12=0 | ✔ standard form (3) | ||
1.1.2 | 3𝑥2+2𝑥−6=0
| ✔ substitution ✔ x = −1,79 ✔ x = 1,12 (3) | ||
1.1.3 | 3𝑥2 − 1 = 27-x OR 3𝑥2 − 1 = 27 − 𝑥3 | ✔ 3−3𝑥−1
✔𝑥2 −1 + 1 = 3−3𝑥 (4) | ||
1.2.1 | 1 +1/𝑥 = 0 𝑥 + 1 = 0 𝑥 𝑥 =−1 or 𝑥=0 | ✔ 𝑥 =−1 (2) | ||
1.2.2 | 𝑥−1/𝑥 =1 1+1/𝑥 𝑥 −1/𝑥=1 +1/𝑥 𝑥2 − 1 = 𝑥 + 1 𝑥2 − 𝑥 − 2 = 0 (𝑥+1)(𝑥−2) = 0 𝑥=−1 or 𝑥=2 𝑥=2 only | ✔ manipulation of equation (5) | ||
QUESTION 2 | ||||
2.1 | 𝑥 − 𝑦 =3 ; 𝑥𝑦 = 28 OR From (1) 𝑦 = 𝑥−3 | ✔ 𝑥 = 𝑦 + 3
✔ 𝑦 = 𝑥 − 3✔ substitute in (2) (6) | ||
2.2 | 𝑥2 ≤ 4 + 3𝑥 ; 𝑥 > 0 𝑥2 − 3𝑥 − 4 ≤ 0 (𝑥+1)(𝑥−4) ≤ 0 Solution −1 ≤ 𝑥 ≤4 But 𝑥 >0 0 < 𝑥 ≤ 4 | ✔ standard form/standaardvorm (4) | ||
QUESTION 3 | ||||
3.1 | 𝑇𝑛 = 𝑎𝑛2 + 𝑏𝑛 + 𝑐 2𝑎 = 2 𝑎 =1 3𝑎 + 𝑏 = 2 3 + 𝑏 = 2 𝑏 = −1 𝑎 + 𝑏 + 𝑐 = 1 1 − 1 + 𝑐 =1 𝑐 =1 𝑇𝑛 = 𝑛2 − 𝑛 + 1 Row 80 Term 1 𝑇80 = 802 − 80 + 1 𝑇80 = 6321 | ✔ a = 1 (5) | ||
3.2 | Row 80 OR Row 80 Term 80 OR
𝑇𝑛 = 𝑛2 + 𝑛 − 1 | ✔ n= 80
✔ calculating term 80 of row
✔ 𝑇𝑛 = 𝑛2 + 𝑛 − 1 (4) | ||
QUESTION 4 | ||||
4.1.1 | 𝑇10 = 𝑆10 − 𝑆9 𝑇10 = 10(11)(12) − 9(10)(11) 𝑇10 = 330 | ✔ setting up of equation ✔ substitution (3) | ||
4.1.2 | 𝑝 ;3𝑝 ;5𝑝 ;…………… OR
| ✔ first three terms
✔ 𝑎 = 𝑝 (4) | ||
QUESTION 5 | ||||
5.1 | 𝑟 = 𝑥+2
| ✔ ratio (2) | ||
5.2 | 𝑆∞= 𝑎
| ✔ substitution ✔ simplification ✔ 𝑥2=16 ✔ both answers (4) | ||
QUESTION 6 | ||||
6.1 | 𝐴 = 𝑃(1−𝑖)𝑛 𝐴 = 635000(1−15/100)5 𝐴 = 281 752,87 | ✔ 𝑖=15/100 and 𝑛 =5 (3) | ||
6.2.1 | 𝑃𝑣 = 𝑥[1 − (1+𝑖)−𝑛] 𝑖 50000 = 𝑥[1− (1 + 16.75/1200)−48] 16.75/1200 𝑥 = 𝑅 1 436,29 | ✔ 𝑖=16.75/1200 (4) | ||
6.2.2 | 𝑃𝑣 = 𝑥[1 − (1+𝑖)−𝑛] OR Outstanding balance (OB) | ✔ 𝑛=−18 (5) ✔ 𝑛=30 (5) | ||
6.3 | 𝐴 = 𝑃(1+𝑖)𝑛 𝐴 = 2𝑥 and 𝑃 = 𝑥 2𝑥 = 𝑥(1+14.75/100)𝑛 𝑛 = log2 log(1 +14.75/100) 𝑛 = 5.04 𝑦𝑒𝑎𝑟𝑠 | ✔ 𝐴 = 2𝑥 and 𝑃 = 𝑥 (4) | ||
QUESTION 7 | ||||
7.1.1 | x = 0 | ✔answer (1) | ||
7.1.2 | x > -2 ; x # 0 | ✔x > -2 (2) | ||
7.1.3 | y = -4 | ✔answer (1) | ||
7.1.4 | 𝑦 = 𝑏𝑥 − 4 5 = 𝑏2 − 4 𝑏2 = 9 𝑏 = ±3 𝑦 = 3𝑥−4 | ✔ sub of −4 (4) | ||
7.1.5 | x = -2 y = -1 | ✔x = -2 (2) | ||
7.1.6 | 𝑦 = 𝑎 −1 𝑥+2 −3 = 𝑎 − 1 0+2 𝑎=−4 𝑦= −4 − 1 𝑥+2 | ✔ sub of asymptotes (3) | ||
7.1.7 | 𝑦 = 𝑥 + 2 −1 𝒚 = 𝒙 + 𝟏 𝑦 = −(𝑥 + 2) −1 𝒚 = −𝒙 − 𝟑 | ✔𝒚 = 𝒙 + 𝟏 (3) | ||
7.2.1 | 𝑦 = log½𝑥 𝑓−1 ∶ 𝑥= log½𝑦 𝑦 = (½)𝑥 OR 𝑦 = 2−𝑥 | ✔swopping of x and y (2) | ||
7.2.2 | ✔Shape (3) | |||
7.2.3 | g(x) = (½)-x OR g(x) = 2x | ✔✔Answer ✔✔Answer (2) | ||
7.2.4 | x > 1 | ✔✔x > 1 (2) | ||
QUESTION 8 | ||||
8.1 | x = -3 | ✔x = -3 (1) | ||
8.2 | 𝑦 = 𝑎(𝑥 + 3)2 − 5 4 = 𝑎(9) − 5 9𝑎 = 9 𝑎 = 1 𝑦 = 𝑥2 + 6𝑥 + 9 − 5 𝑦=𝑥2 + 6𝑥 + 4 𝑎 = 1 and 𝑏 = 6 | ✔ sub of turning point (3) | ||
8.3 | Δ = 𝑏2 − 4𝑎𝑐 Δ = 36 − 4(1)(4) Δ=20 𝑅𝑜𝑜𝑡𝑠 𝑎𝑟𝑒 𝐼𝑟𝑟𝑎𝑡𝑖𝑜𝑛𝑎𝑙 𝑎𝑛𝑑 𝑈𝑛𝑒𝑞𝑢𝑎𝑙 | ✔ Δ=20 (3) | ||
8.4 | 𝑔(𝑥) = 2𝑥 Point (−2;−4) OR 𝑓(𝑥) = 𝑥2 + 6𝑥 + 4 | ✔ 𝑔(𝑥) = 2𝑥
✔ derivative (4) | ||
QUESTION 9 | ||||
9.1 | 𝑓(𝑥) = 3𝑥2 − 1
| ✔ formula (5) | ||
9.2.1 | 𝑦 = 5𝑥2 + √𝑥 𝑦 = 5𝑥2 + 𝑥½ 𝑑𝑦/𝑑𝑥 = 10𝑥 + ½𝑥−½ | ✔𝑥½ (3) | ||
9.2.2 | 𝐷𝑥 [6𝑥−4] 3𝑥 𝐷𝑥[6𝑥/3𝑥−4/3𝑥] 𝐷𝑥[2 − 4/3𝑥−1] =−4/3𝑥−2 or 4/3𝑥2 | ✔ 2 (3) | ||
9.2.3 | 𝑚 = 𝑠′(𝑡) =3𝑡2 𝑡2 ≥ 0 3𝑡2 ≥ 0 ∴ no value of t will make 𝑠′(𝑡) negative. | ✔ derivative (2) | ||
QUSTION 10 | ||||
10.1 | 𝑓(𝑥) = 𝑥3 − 𝑥2 − 8𝑥 + 12 OR 𝑥+3 3𝑥2 − 12𝑥 + 12 | ✔(𝑥−2)
(4) | ||
10.2 | 𝑓′(𝑥) = 3𝑥2 − 2𝑥 − 8 = 0 (3𝑥 + 4)(𝑥 − 2) = 0 𝑥 = −4/3 or 𝑥 = 2 𝑓(−4/3) = (−4/3)3 −(−4/3)2 − 8(−4/3) +12 B(−4/3; 500/27 ) | ✔𝑓′(𝑥) (5) | ||
10.3 | 𝑓′′(𝑥) = 6𝑥 − 2 OR 𝑥=−4/3+2 | ✔𝑓′′(𝑥) = 6𝑥 − 2 (2) | ||
10.4 | 𝑥 <−4/3 or 𝑥 > 2 | ✔𝑥 <−4/3 (2) | ||
10.5 | 𝑦=𝑘 ;𝑘<0 Only one Real Root | ✔answer (2) | ||
QUESTION 11 | ||||
11.1 | 𝐷(0) = 3 + ½(0)2 −14(0)3 𝐷(0)=3 𝑚 | ✔𝐷(0)=3 𝑚 (1) | ||
11.2 | 𝐷′(𝑡) = 𝑡 − ¾𝑡2 𝐷′(3) =3 −¾(3)2 =3 − 27/4 =−15/4 m/h / m/u | ✔𝐷′(𝑡) (3) | ||
11.3 | Decreasing | ✔Decreasing (1) | ||
11.4 | 𝐷′(𝑡 )= 0 𝑡− ¾𝑡2 = 0 4𝑡 − 3𝑡2 = 0 𝑡(4 − 3𝑡) = 0 𝑡 = 0 or 𝑡 = 43 43 =1ℎ20𝑚𝑖𝑛 Time: at 08h00 or 9h20 | ✔𝐷′(𝑡 )= 0 (4) |
QUESTION 12 | |||
12.1 | 12.1.1 | P(A′) = 1 − P(A) | ✔ P(A′) = 1 − P(A) (2) |
12.1.2 | P(AandB) = 0 | ✔ answer (1) | |
12.1.3 | P(A or B) = 0,35 + 0,52 | ✔ P(A or B) = P(A) + P(B) (2) | |
12.2 | 12.2.1 | 6! = 720 | ✔ 6! or/of 720 (1) |
12.2.2 | 4! | ✔4! (2) | |
12.2.3 | 2!.5! = 240 = 1 OR 0,333 | ✔ 2! (4) | |
TOTAL: 150 |