TECHNICAL MATHEMATICS PAPER 1
GRADE 12
NATIONAL SENIOR CERTIFICATE
MEMORANDUM
JUNE 2018
NOTE:
QUESTION 1 | |||
1.1 | 111010 | 🗸🗸Accurate value | |
1.2 | 1.2.1 | x(x - 3) = 0 | 🗸🗸Each correct x-value (2) |
 | 1.2.2 | x2 + 3x +1 = 0 (correct to ONE decimal) x = -3 ± √(3)2 - 4(1)(1) (-1 Mark for incorrect rounding) OR | 🗸 Formula 🗸Substitution 🗸 x ≈ -0,4 🗸 x ≈ -2,6 🗸 Each x value 🗸 Expansion 🗸Quadratic factors 🗸 x ≈ -0,4 🗸 x ≈ -2,6 (4) |
 | 1.2.3 | x2 + 3x + 2 < 0 => | 🗸Standard form 🗸Critical values 🗸Notation 🗸Both values OR 🗸 🗸 🗸 -2 < x < -1 Accurate answer 🗸 -2< x x < -1 (4) |
1.3 | y = x2–1 …………. (1) and  y = x+1.................... (2) | 🗸Equating (1) and (2) 🗸Standard form 🗸Factors 🗸Both x-values 🗸Both y-values (5) | |
1.4 | b2– 4ac = 0 | 🗸Discriminant = 0 🗸Substitution 🗸🗸Each value of b (4) | |
 [21] |
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QUESTION 2 | ||
2.1 | 2x.21– 2x.2–1 = 2x(2 – 2–1) | 🗸Prime bases 🗸 Factor 2x 🗸 Factor 2 – 2–1 🗸 ½ (4) |
2.2 |  | 🗸Log Rule(numerator) 🗸Log Rule (denominator) 🗸Simplification  loga 5  –1 🗸Power rule 🗸Prime factors of 25 🗸Prime factors of 125 🗸Power rule (numerator) 🗸Power rule (denominator) 🗸Simplification (5) |
2.3 2.3.1 | Rabbits = 1000 × 20,05(30) | 🗸Substitution 🗸Answer (2) |
2.3.2 | 8000 = 1000 × 20,05t 8 = 20,05t | 🗸Substitution 🗸log form 🗸 t = 60 days (3) |
 |  | [14] |
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QUESTION 3 | ||||||
3.1    | 3.1.1 | | Z |= √(–2)2  + (1)2 | 🗸Substitution 🗸Answer (2) | |||
3.1.2 |  | 🗸Quadrant 🗸Point/Coordinates (2) | ||||
3.1.3 | tanθ = –½ Accept angles in radians | 🗸tan ratio 🗸Ref Angle 🗸Argument (3) | ||||
3.1.4 |  | Z |= √5 Accept angles in radians z = √3cis (153, 43o ) | 🗸🗸Accurate polar form (2) | ||||
3.2 | (x - yi) = –2+ i OR 1(x - yi) + i(x - yi) = –2 + i x+ y = -2.............. (1) (1)+(2) : x = -½ | 🗸Simplification 🗸Conjugate product 🗸Simplification 🗸 x-value 🗸 y-value 🗸 Multiplication 🗸Simplification 🗸Comparing real values and imaginary values 🗸 x-value 🗸 y-value (5) | ||||
[14] |
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QUESTION 4 | |||
4.1   | 4.1.1 | inorm  = 14% = 0, 035 | 🗸 Answer (1) |
4.1.2 |  | 🗸Formula 🗸Substitution 🗸Interest (3) | |
4.1.3 | A = 2500(1 + 0, 035)7×4 | 🗸Substitution 🗸Correct i = 0,035 and n = 21 🗸 Value of A (3) | |
4.2 Â | Â | In A1 i = 0, 08 (8) | |
 |  |  | [15] |
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QUESTION 5 | |||
5.1       | 5.1.1 | 0 = – ( x – 3)2  + 4 OR | 🗸h(x) =0 🗸Transposition 🗸A co-ordinates 🗸B co-ordinates 🗸h(x) =0 🗸Factors 🗸A coordinates 🗸B coordinates (4) |
5.1.2 | h(x) = -x2+ 6x - 5 | dy 🗸Coordinates (2) | |
5.1.3 | x ∈ [0; 6] OR 0 ≤ x ≤ 6 | 🗸0 🗸6 🗸Correct notation (3) | |
5.1.4 | Maximum height = 4 units | 🗸Answer | |
5.1.5 | y-intercept of h = –5 | 🗸y-intercept 🗸 5 units (2) | |
5.1.6 | y ≤ 4 OR y Î (-∞; 4] OR - ∞ < y ≤ 4 | 🗸 Notation 🗸 Value(s) (2) | |
5.1.7 | x ∈ [3;5] OR 3 ≤ x ≤ 5 | 🗸3 🗸5 🗸Correct notation (3) | |
5.2 | No. The truck height (4,5) is greater than the | 🗸 No 🗸 Bridge less than truck height OR Truck height greater than the bridge height 🗸Cross bar (3) | |
5.3 | At F, x = 3 y = – 3+5 =2 FD = D – F | 🗸y-value at F 🗸Subtracting y-values 🗸 FD (3) | |
 |  | [23] |
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QUESTION 6 | |||
6.1   | 6.1.1 | 0 = –2 + 1 | 🗸y =0 🗸 Coordinates (2) |
6.1.2 | f(x) = 20 y =1 | 🗸 Value of y (1) | |
6.1.3 | y=0 for f(x) x = 0 and y =1 for g(x) –1 Mark for 1 omitted asymptote  | 🗸y =0 🗸x =0 and y=1 (2) | |
6.2 |  | 🗸Shape of f 🗸 y-intercept of f 🗸 y=1 Asymptote of g 🗸 1 more point on f 🗸Shape of g 🗸 1 more point on g 🗸 x- intercept of g (7) | |
6.3  | 6.3.1 | x ∈ R, x ≠ 0 | 🗸Restriction 🗸Domain value (2) |
6.3.2 | x ∈ (0; +∞ ) OR x > 0 | 🗸Correct inequality (1) | |
 |  |  |  [15] |
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QUESTION 7 | ||||
7.1 | f (' x)= lim  f ( x+ h) –  f ( x) f '(x)= lim –2 ( x+ h)2  – (–2x2 ) f (x)= lim –2x2 – 4xh – 2h2 + 2x2 | 🗸Formula 🗸Substitution 🗸Expansion 🗸Factors 🗸 f '(x)= –4x (5) | ||
-1 Mark for incorrect notation in 7.1 or 7.2 | ||||
7.2 | y = 2√x – 1 dy = x½ + x-2 OR dy = 1 + 1 | 🗸2x½ 🗸x-1 🗸 x½ 🗸x-2 | ||
7.3 | g'(x) = 2x - 2 | 🗸 g'(x) 🗸 mtangent 🗸(2;0) 🗸 c = – 4 🗸 y = 2x – 4 (5) | ||
 |  | [14] |
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QUESTION 8 | ||
8.1 | f (–1) = (–1)3 + 4(–1)2 + (–1) – 6 | 🗸f (–1) = – 4 ≠0 |
8.2 | f (1) = (1)3 + 4(1)2 + (1) - 6 = 0     1       4        1          -6 f(x) = (x–1) (x2+5x+6) | 🗸 f(x) =0 🗸 First linear factor 🗸Quadratic factor 🗸Factors of x2+5x+6 🗸All coordinates (5) |
8.3 | y-intercept = –6 | 🗸Answer (1) |
8.4 | f '(x)= 3x2+ 8x+1 | 🗸 f '(x) = 0 🗸x- values (-0,13; -6,06) (-2,54; 0,89) OR Y – coordinates of TP 🗸 y= -6, 06 🗸 y= 0,89 |
8.5 |  | 🗸Shape 🗸x-intercepts 🗸Max. Turning point 🗸Min. Turning point 🗸 y-intercepts (5) |
 |  | [16] |
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QUESTION 9 | |||
9.1   | 9.1.1 | Surface Area = 2(2x.x +2x.h + x.h) ∴ h = 120 - 4x2 | 🗸 Formula 🗸Substitution 🗸 Simplification 🗸 h (3) |
9.1.2 | V = l.b.h | 🗸V = l.b.h 🗸Substitution (2) | |
9.1.3 | dV = 40 – 4x2 | 🗸 dV 🗸 x = 10 ≈ 3,16 cm3 (3) | |
9.2 |  | T = t3 - 9t 2+ 50t - 66 | 🗸 3t 2 -18t + 50 🗸Substitution by 5 dT =35 C.s-1 (3) |
 |  |  | [11] |
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QUESTION 10 | ||
10.1  |  | 🗸 x3 🗸 - x 2 🗸 c |
10.2 |  | 🗸Integration expression 🗸Simplification 🗸Substitution by 1 and 0 🗸 1 square units (4) |
 |  | [7] |
TOTAL:150