1. Ronald Hui Tak Sun Secondary School
HKDSE Mathematics
Ronald Hui
Tak Sun Secondary School

2. Standard Quiz Result of Standard Quiz Major Problems Full mark: 30
Highest: 24 (6)
Lowest: 0 (x3) – You are still not alone!
Average: 6.83 (1.2)
Number of students (10-14): 6
Number of students (0 – 9): 17
Major Problems
Good try in drawing the lines; but forget to shade the areas
Still no much ideas in this topic

3. Standard Quiz Result of Standard Quiz 6th: HO Yat Wan, Owen (2)
YEUNG Choi Sum, Sam (NEW)
4th: WAN Yu Hin, Daniel (NEW)
CHAN Chun Hang, Jason (NEW)
2nd: WONG Vincent Wai Shun (1)
WONG Yin Man Marco (=)
1st: CHEUNG Ka Chun, Nathan (=)
Congratulations!!! Well done!!!

4. Standard Quiz (24) Result of Standard Quiz Major Problems
Full mark: 24
Highest: 22
Lowest: 2
Average: (2.46)
Number of students (10-11): 2
Number of students (0 – 9): 11
Major Problems
Draw the lines carelessly.
Solid lines vs dotted lines

5. Standard Quiz (24) Result of Standard Quiz (24)
6th: GURUNG Tashi Chiring (2)
HUI Ka Ho, Ken (NEW)
WAN Hang Nam, Hanki (NEW)
WONG Yin Man Marco (5)
5th: WONG Vincent Wai Shun (3)
4th: YEUNG Choi Sum, Sam (2)
3rd: CHAN Chun Hang, Jason (NEW)
2nd: HO Yat Wan, Owen (3)
1st: CHEUNG Ka Chun, Nathan (NEW)
Congratulations!!! Well done!!!

6. Missing Homework RE2 SHW2-R1 SHW2-P1 Kelvin Charles
Daniel, Kelvin, Charles
22 October 2015
Ronald HUI

7. Missing Homework SHW3-01, SHW3-A1, SHW3-B1 SHW3-C1 SHW3-E1 SHW3-R1
Charles
SHW3-C1
Daniel, Sam L, Charles
SHW3-E1
Kelvin, Charles
SHW3-R1
Daniel, Charles
SHW3-P1
Kelvin, Charles, Issac, Marco S (RD)
22 October 2015
Ronald HUI

8. Missing Homework SHW4-01: Missing 3 SHW4-A1: Missing 8
SHW4-B1: Missing 9
SHW4-C1: Missing 13
SHW4-D1: Missing 14
SHW4-R1: Missing 15
SHW4-P1: Missing 17
RE4: Missing 17
22 October 2015
Ronald HUI

9. Missing Homework Chapter 5 HW Deadline: Today! (3 Dec) SHW5-01: Only 7
SHW5-A1: Only 6
SHW5-B1: Only 4
SHW5-C1: Only 5
SHW5-D1: Only 3
SHW5-E1: Only 2
SHW5-F1: Only 1
SHW5-R1: None!
SHW5-P1: None!
Deadline: Today! (3 Dec)
22 October 2015
Ronald HUI

10. Similarly, for any △ABC, we have:
the included angle of a and b. 2 1
ab sin C =
Area of △ABC A A
= bc sin A 2 1 b b b c c c
= ac sin B 2 1 B B C C a a a
the included angle of b and c.
the included angle of a and c.
Note: The above formula is also valid for right-angled triangles.
When C = 90,
area of △ABC

11. Heron’s formula Area of △ABC s(s  a)(s  b)(s  c) , where s
s is called the semi-perimeter.

12. a sin A = b sin B c sin C The sine formula A a B b C c In △ABC,
It can also be written as = b
sin B c
sin C
sin A a
Note: By the sine formula, we have: 1.
2. sin A : sin B : sin C = a : b : c

13. In fact, for any △ABC, we have
c2 = a2 + b2  2ab cos C
Similarly, we can prove that
b2 = a2 + c2  2ac cos B
and a2 = b2 + c2  2bc cos A.
The above results are known as the cosine formula.
The cosine formula
In △ABC, A C a b c B
a2 = b2 + c2  2bc cos A,
b2 = a2 + c2  2ac cos B,
c2 = a2 + b2  2ab cos C.

14. The cosine formula can also be written as follows:
In △ABC, A C a b c B
The cosine formula is also known as the cosine law or the cosine rule.

15. = In the figure, CB and AD are horizontal lines. B C
angle of depression of A from B
angle of elevation of B from A
We can see that:
Angle of elevation of B from A
Angle of depression
of A from B =
alt. s, AD // CB

16. True Bearing and Compass Bearing
To describe the direction of a point relative to another point, true bearing or compass bearing may be used. N O P
Directions are measured from the north in a clockwise direction.
It is expressed as x, where
(i) 0  x < 360,
(ii) the integral part of x must
consist of 3 digits. N O P Q
58
40
Refer to the figure on the right,
the true bearing of P from O is
058,
180 + 40
= 220
the true bearing of Q from O is
220.

17. True Bearing and Compass Bearing
Directions are measured from the north
N60W
N40E N S
or the south. P Q
60
40
It is expressed as NxE,
NxW, W E
SxE
or SxW, O
70
25
where 0 < x < 90. S R S
S70W
S25E