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secondary 4 | A Maths
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genevieve
Genevieve

secondary 4 chevron_right A Maths chevron_right Singapore

Very confused on how to solve these qns. Would appreciate detailed worked solution. Thanks!!

Date Posted: 4 years ago
Views: 394
snell
Snell
4 years ago
14.
cos (60° - θ )
= cos 60° cos θ + sin 60° sin θ
= 0.5 cos θ + √3/2 sin θ


3 sin θ + 4 cos (60° - θ ) = 2
=> (3+√3/2) sin θ + 4.5 cos θ = 2

do the R formula

. . .

15.
tan θ = 2/x
x = 2 cot θ

OA = 5 + x = 5 + 2 cot θ

sin θ = OM/OA
OM = (5 + 2 cot θ) . sin θ
= 5 sin θ + 2 cos θ

(i) do the R formula
R is the max. value

. . .


16.
area of AOB = 0.5 . 4² . sin x = 8 sin x

area of COD = 0.5 . 6² . sin (90° - x)
= 18 cos x

S = 8 sin x + 18 cos x

do the R formula
S = R sin (x - α)

. . .

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
Good evening Cheryl! Here are my workings for Q14.
genevieve
Genevieve
4 years ago
Thank you!
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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Good evening Cheryl! Here are my workings for Q15 (ii) and Q16.
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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Good evening Cheryl! Here are my workings for Q15 proving part and Q15 (i).
15

https://drive.google.com/file/d/1_nGZCejct0Lvdqn1PzRCMnSUTot3WHnU/view?usp=drivesdk
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PrimaryOne
Primaryone's answer
180 answers (A Helpful Person)