MATHEMATICS P2
GRADE12
JUNE2016
MEMORANDUM
NATIONAL SENIOR CERTIFICATE
QUESTION
1.1 |
| (4) | ||||||||||||||
1.2 | 40 ≤ t < 60 | ✓answer (1) | ||||||||||||||
1.3 | 172 | ✓answer (1) | ||||||||||||||
1.4 | (72;148) ∴ 172-148 = 24 learners | ✓148 ✓24 (2) | ||||||||||||||
1.5 | Frequency: 30; 39; 60;28;10;5 30×10+39×30+60×50+28×70+10×90+5×110=7880 172 =7880 172 =45,81 | ✓frequency ✓midpoints ✓7880 172 ✓answer(4) |
[12]
QUESTION 2
2.1 | 𝑥̅= 6772 20 𝑥̅=338,6 𝑚𝑙 | ✓ 𝑥̅= 6772 20 ✓answer(2) |
2.2 | 2,71 ml | ✓✓ answer (2) |
2.3 | [338,6 – 2,71; 338,6 + 2,71] [335,89; 341.31] | ✓✓ interval (2) |
[6]
QUESTION 3
3.1 | 𝑚𝐴𝐶= −1 𝑦−9=3(𝑥−3) 3𝑥−𝑦=0 | ✓S ✓R ✓ subst, m = 3 & (3;9) in eqn. (3) |
3.1.2 | 𝑥+3𝑦=10……… .(1) 3𝑥−𝑦=0 …………(2) 𝑥+3(3)=10 𝑥=1 | ✓equating two eqns ✓simplification ✓y = 3 ✓x = 1 (4) |
3.1.3 | ✓method using midpoint ✓ simplification ✓ coordinates of B (3) | |
3.1.4 | AD =√(3−𝑥)2+ (9−𝑦)2 ∴ √50= √9−6𝑥+𝑥2+81−18𝑦+ 𝑦2 ∴ 50= 𝑥2−6𝑥+𝑦2−18𝑦+90 ∴ (10−3𝑦)2−6(10−3𝑦)+ 𝑦2−18 𝑦+90=50 ∴ 100−60𝑦+9𝑦2−60+18𝑦+𝑦2−18𝑦+90=50 | ✓ subst into eqn dist AD ✓ subst AD = √50 ✓subst x =10 - 3y ✓ simplification ✓standard form ✓values for y ✓values for x ✓coordinates (8) |
3.2.1 | 𝑚PQ= 8 - 2= 6 = ¾ | ✓ subs into eqn ✓ answer (2) |
3.2.2 | tan𝜃= ¾ 𝜃=36,9 | ✓ tan 𝜃 ✓ answer |
3.2.3 | 𝑦=¾𝑥+𝑐 0= ¾(8)+𝑐 𝑐= −6 𝑦= ¾𝑥−6 | ✓subst. m = 34 ✓ answer |
[25]
QUESTION 4
4.1 | A(0; y) ∴𝑝= 0+8=4 2 ∴D(4;4) | ✓midpt equation ✓coordinates of D (2) |
4.2 | Ay = 𝑦+7=4 A(0; 1)2 ∴(𝑥−0)2+(𝑦−1)2= 𝑟2 ∴(4−0)2+(4−1)2= 𝑟2 ∴16+9= 𝑟2 ∴𝑥2+(𝑦−1)2=25 ∴𝑥2+ 𝑦2−2𝑦−24=0 | ✓ y-coordinate of A ✓ A(0; 1) ✓✓subst (0;1)and (4;4) into equation. ✓r2 (5) |
4.3 | 𝑚𝐴𝐵×𝑚𝐹𝐷𝐸= −1 [tan radius] | ✓S/R 3 ✓subst m and (4;4) into eqn |
4.4 | 𝑥2+ 𝑦2= 𝑟2 (8)2+(7)2= 𝑟2 ∴𝑥2+ 𝑦2=113 | ✓subst (8;7) into eqn ✓answer (2) |
[14]
QUESTION 5
5.1.1 | =sin𝑥.cos𝑥.tan𝑥.cos𝑥 | ✓sin x ✓cos x ✓tan x ✓cos x ✓sin x ✓cos x ✓-tan x ✓-cos x (8) |
5.2 | sin𝑥 + 1 + cos𝑥 = 2 2+2cos𝑥 2 = RHS/RK | ✓ denominator ✓ numerator ✓ simplification ✓ identity ✓ factorisation (5) |
5.3 | cos2𝑥=cos(𝑥+𝑥) = cos𝑥.cos𝑥−sin𝑥.sin𝑥 =cos2𝑥−sin2𝑥 = cos2𝑥−(1−cos2𝑥) =2cos2𝑥−1 | ✓ expansion ✓ identity (2) |
5.4 | cos2𝑥+3sin𝑥=2 1−2sin2𝑥+3sin𝑥=2 2sin2𝑥−3sin𝑥+1=0 (2sin𝑥−1)(sin𝑥−1)=0 | ✓ identity ✓ standard form ✓factors ✓ sin x = ½ sin x = 1 (both eqns) ✓ x = 30° ✓ x = 150° ✓ x = 90° (7) |
5.5 | sin𝐴cos𝐵+cos𝐴sin𝐵=sin(𝐴+𝐵) = sin90° = 1 | ✓ identity ✓ subst ✓ answer (3) |
[25]
QUESTION 6
6.1 | ✓shape g ✓intercepts ✓min & max value ✓shape f ✓asymptotes ✓ intercept (6) | |
6.2 | −180°<𝑥≤−90° or/of 0°≤𝑥≤90° | ✓critical values ✓ notation (2) |
[8]
QUESTION 7
7.1 | MN2=PN2+PM2−2PN.PMcos MP̂N = 122+102−2(12)(10)cos126,9° =144+100−240(−0,6) =388,1 MN=19,7 𝑚 MN=AD=19,7 𝑚 | ✓ correct subst into cos rule ✓ simplification ✓ answer (3) |
7.2 | ½MN.PT= ½PN.PMsinMP̂N [Both equal Area of ΔPMN] PT=12.sin126,9° | ✓ Equating Area form ✓ correct subst ✓ simplification ✓ answer (4) |
[7]
QUESTION 8
8.1 | Supplementary | ✓ answer (1) |
8.2.1 | EF̂O=90° [tan radius] EF̂O+EĜO=180° | ✓ S ✓R ✓S ✓R ✓ R (5) |
8.2.2 | Ĝ1= Ĥ=𝑥 [ tan chord] K̂1= Ĥ=𝑥 [ corresp angles; EK || FH] ∴Ĝ1= K̂1 EG is a tangent [angle between line and chord] | ✓S ✓R ✓S ✓R ✓R (5) |
8.2.3 | Ô1=2Ĥ [ angle at centre] = 2x ∴FÊG=180°−2𝑥 [ opp angles of cyclic quad] | ✓S ✓R ✓R (3) |
[14]
QUESTION 9
9.1 | B̂2 = Â2 = x [ angles opp equal sides] Â1 = B̂2 = x [ tan chord] Ŝ1 = Â1 = x [ corresp; AD||SC] 𝐵̂3 = 𝐴̂2 = x [ alt int; AD|| SC] AD̂C = B̂3 = x [ ext angle of cyclic quad] | ✓ S/R ✓ S/R ✓ S/R ✓ S/R ✓ S/R (5) |
9.2 | Â1 = AD̂C [ from 8.1] AS || DC [alt angles equal] DA || CS [given] ASCD is a parallelogram [opp sides ||] | ✓ S ✓ S/R ✓ S ✓ R (4) |
9.3 | ΔSAB ||| ΔADB [ A,A,A]/[H,H,H] | ✓ ΔSAB (1) |
9.4 | SA = SB [from 8.3.1] ∴AD.SB=SA.AB | ✓ S ✓ S ✓ S/R ✓ S/R ✓ R (5) |
[15]
QUESTION10
10.1.1 | In proportion | ✓ Answer (1) |
10.1.2
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RTP: PROOF: But Area ΔBDE=Area Δ CED (same base and same height) ∴ areaΔADE = area ΔADE | ✓ ratio of area of ΔADE: ΔBDE ✓AD BD ✓ratio of area of ΔADE : ΔCED ✓AE EC ✓equating two areas(5) |
10.2.1 | QT=QW prop thm; TW || VR ∴ 15 = 𝑥+4 𝑥2−9𝑥+8=0 ∴(𝑥−8)(𝑥−1)=0 ∴𝑥=8 or 𝑥=1 | ✓QT=QW TP WR ✓R ✓ substitution ✓ std form ✓factors ✓ both values for x (6) |
10.2.2 | PV = PT prop thm TV || QR PV = 10 PV = 12units | ✓ S/R ✓ substitution ✓ answer (3) |
[15]
QUESTION11
11.1 | 𝐷2=90° [ line from centre to midpoint of chord] ∴ΔABC |||ΔDOC [AAA/𝐻𝐻𝐻] | ✓ S/R ✓ S/R ✓ S (3) |
11.2 | OC = DC ΔABC |||ΔDOC OC = DC.BC
| ✓ S/R (1) |
11.3 | AC2=BC2−AB2 [Pythagoras] 𝑂𝐶=𝐷𝐶.𝐵𝐶 𝐴𝐶 = 15 × 30=18,8 𝑐𝑚 24 | ✓ S/R ✓ subst in eqn ✓ AC = 24 ✓ subst ✓ answer (5) |
[9]
TOTAL: 150