O-Level Additional Math

[tianzhu]

Hi teddy7171


In order to solve this question, students need to understand the concepts of Scales and Maps. You may refer to your son’s textbook for a more detailed explanation.

A scale of 1:p means that 1cm represents pcm
Therefore 12cm represent 12pcm in map P

Likewise, 16cm represent 16qcm in map Q

The same street is represented by different scales as in map P and Q
12p=16q
Hence p/q = 4/3

Here p is given as 5000
p/q = 4/3
5000/q = 4/3
Hence q = 15000/4 = 3750

Best wishes

[Sahimi]

Hi! pls help!!


If n is a number, show that for all values of n, (n3 + 11n) is divisible by 6. (sec Two maths)
Thks

[iFruit]

Sahimi:

Hi! pls help!!


If n is a number, show that for all values of n, (n3 + 11n) is divisible by 6. (sec Two maths)
Thks

n³ + 11n = n³ -n + 12n = n(n²-1)+12n = n(n-1)(n+1)+12n = (n-1)n(n+1)+12n


(n-1)n(n+1) is the product of 3 consecutive numbers which is always divisible by 6 ( you can use induction to prove if necessary) and 12n is divisible by 6.

So, n³ + 11n is divisible by 6

HTH

[Sahimi]

iFruit:

Sahimi:

Hi! pls help!!


If n is a number, show that for all values of n, (n3 + 11n) is divisible by 6. (sec Two maths)
Thks

n³ + 11n = n³ -n + 12n = n(n²-1)+12n = n(n-1)(n+1)+12n = (n-1)n(n+1)+12n


(n-1)n(n+1) is the product of 3 consecutive numbers which is always divisible by 6 ( you can use induction to prove if necessary) and 12n is divisible by 6.

So, n³ + 11n is divisible by 6

HTH

thks very much, iFruit.

[k1ndan]

E:{x:30<x<=100}

A:{x: Multiples of 3}
B:{x: unit digit is 10}

What is A’n B’?[/url]

[k1ndan]

http://i300.photobucket.com/albums/nn19/k1ndan/Maths_Sec2_Set1.jpg\">

[k1ndan]

k1ndan:

http://i300.photobucket.com/albums/nn19/k1ndan/Maths_Sec2_Set1.jpg\">

Sorry, typo error, the condition should be if a=b, what is the value of W?

[k1ndan]

€ = {x : x is an integer, 30 < x≤100}

A: {x : x is divisible by 3}
{x: units digits of x is 0}

List the elements of A’ n C’

[Guan Hui]

since a+b=Q and Q=32 and a=b

a= 16, b=16
since c+b=P and P=46 and b=16
c=30
a+b+c= 16+16+30= 62(impossible since E=60)
E-(a+b+c)=W=60-62= -2 (unless negative is accepted as the ans?)


[/quote]

[Sahimi]

Hi pls help!


The two parallel sides of a trapezium are 3x and (5x + 8)cm each. Given the height between the parallel lines is (x - 1)cm. Show that the area is 4(x2 - 1).