F.5 MATHS QUESTIONS!!(20點)

回答 (2)

2014-03-10 7:37 pm
✔ 最佳答案
11
Sol
設成本=x元,標價=y元
y=1.5x
0.8y-x=2
1.2x-x=2
x=10
(B)

21
F在AB上,AB┴CF
CF=BC*Sinx
G在CF上,DG┴CF
CG=CD*Cosy
AD=CF-CG=BC*Sinx-CD*Cosy
(B)

22
13^2=5^2+12^2
SinB=12/13
TanA=5/12
SinB:TanA=(12/13):(5/12)
=(12/13)*(12/5)
=144/65
(D

42
∠ABE=∠ECD=β
∠EAB=∠EDC=α
Sinα/BE=Sinβ/AE
AE/BE=Sinβ/Sinα
(D)

43
AO為切線
CD中點E
BE=4
CE^2=(5-4)*(5+4)

CE=3
OD=OE+DE=5+3=8
(D)

44
BC=32,AC=24,AB=16
S=(32+24+16)/2=36
√[36*(36-32)*(36-24)*(36-16)]
=√36*√960
△BPX=√960=8√15
(B)

45
設C(p,-p)
AB直線方程式:-2x+y=-15
-2p-p=-15
p=5
(x-p)^2+(y+p)^2=p^2
(x-5)^2+(y+5)^2=25
(B)

2014-03-10 9:03 am
Q10: 設成本為X, 標價為Y
Y=X(1+50%)
Y=1.5X
1.5X-Y=0----1

0.8Y=X+2
X-0.8Y=-2----2

解1式同2式,可得出X=10,Y=15
所以成本為$10.

Q21:AB上加一點F 令到FC垂直AB,AE上加一點G令到CG垂直AE

FC/BC=sin x
FC=BCsin x

DG/CD=cos y
DG=CDcos y

AD=FC-DG=BCsin x-CDcos y

Q22:三條邊比例13:5:12
5^2+12^2=13^2 所以呢個係直角三角形

sin B=12/13
tan A=5/12
sinB: tanA
=12/13:5/12
=144:65

2014-03-10 01:09:46 補充:
Q42.













2014-03-10 01:12:49 補充:
BAE=sin a , ABE=sin b (



2014-03-10 01:13:03 補充:
(s in the same segment)
by sine law, AE/sin b=BE/sin a AE/BE=sin b/sin a
ANS:D

2014-03-10 01:15:03 補充:
43. Let X be a point on CD so that CD perpendicular to BX.
BX=4 , BD=radius=5
BX^2+DX^2=BD^2
4^2+DX^2=5^2
DX=3
OD=3+5=8
ANS:D

2014-03-10 01:52:20 補充:
Q44.
BY cosine law, COS BCY=(32^2+24^2-16^2)/(2x32x24)
BCY=28.9550
BY^2=32^2+12^2-2(32)(12)(cos28.9550)
BY=22.2711
cos CBY=(32^2+22.2711^2-12^2)/(2x32x22.2711)
CBY=15.1207

cos CBZ=0.6875 CBZ=46.5675
BXA=(180-46.5675)/2=66.7163(BX=AB)
BPX=180-15.1207-66.7163=98.1630
XP/sin15.1207=16/sin98.1630

2014-03-10 01:52:25 補充:
XP=4.2164

AREA OF BPX=0.5X16X4.2164Xsin 98.1630=33.3892
答案無,有可能出錯....

2014-03-10 01:58:02 補充:
Let the circle touch the y-axis at point D and r be the radius
ADC~AOB(AAA)
AO=15,OB=7.5

(15-r)/15=r/7.5
15-r=2r
3r=15
r=5

so the coordinates of C are(5,-5)

so that the equation is provided by
(x-5)^2+(y+5)^2=5^2
x^2-10x+10y+25=0
ans is B

2014-03-10 12:11:19 補充:
Q44. 琴晚唔小心做錯左

AREA OF BPX=0.5X16X4.2164Xsin 66.7163=30.9839=8開方15
ans is b


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