Math Paper 4

[ismailb_1993]

As we all know, the last question will probably be on sequences....does anyone have any useful notes regarding them??

[ismailb_1993]

and maybe some tips on graphs would help?

also i had a question in regards to function graphs...
sometimes you have to plot the points of a function...and they sometimes ask to find the inverse of a point for intance f^-1(5)...in this case what should i do?

[BusinessMaNiac! ( Shizzle)]

First find the inverse..
then the answer u get, use it on the x-axis....

Sometimes they give gf(x)...
In this case, u wud start from the Left eh?

[ismailb_1993]

First find the inverse..
then the answer u get, use it on the x-axis....

Sometimes they give gf(x)...
In this case, u wud start from the Left eh?

shazil? if ive mistaken you then sorry

but i see this questions are usually worth 1 mark...and the process you have outlined is worth atleast 3 marks.

[pap19]

pls tell me fast hot to do entire question no3 of maths paper 4 oct/nov 2000

[ismailb_1993]

pls tell me fast hot to do entire question no3 of maths paper 4 oct/nov 2000

you can use the cos rule for the first question...you know three of the lengths of the triangle that is 4,5,6. calc as follows:

to find abc
(4^2+5^2-6^2) / (2x4x5)

when you get the answer of that you use cos^-1 and you get the angle ABC

for B.) and C.) ill have to draw it which i obviously cant do here.

[Saavya]

'Common Difference' Sequences

The general term for term number 'n' , common diff. 'd' and first term 'a'is:

dn + (a-d)

Find the nth term in this sequence : 13, 20, 27, 34, 41, 48 ...

a=13, d= 7

nth term = dn + (a-d) = 7n + (13-7) = 7n +6

this is one way of finding the nth term but its long i knoww

i get confused with the other ones though

[Aayesha]

yeah ..but how to find it when there is no common difference between the terms ?

[ismailb_1993]

yeah ..but how to find it when there is no common difference between the terms ?

those are the other ones she's talking about

[ismailb_1993]

'Common Difference' Sequences

The general term for term number 'n' , common diff. 'd' and first term 'a'is:

dn + (a-d)

Find the nth term in this sequence : 13, 20, 27, 34, 41, 48 ...

a=13, d= 7

nth term = dn + (a-d) = 7n + (13-7) = 7n +6


this is one way of finding the nth term but its long i knoww

i get confused with the other ones though

thanks alot!!! thats really helpful!!

[Aayesha]

oh okay. Thanks 

[diva_sparkles]

thanks alot!!! thats really helpful!!

no actualy this is used whn there is a common difference!!
otherwise u hv to find someother way 2 do it

[Saavya]

'Changing Difference' Sequences

The general term for term number 'n' , common diff. 'd' , first term 'a' and difference change 'c'is:

a+d(n-1)+c/2(n-1)(n-2)

i cant remember this one its long and u have to solve so many steps in order to reach the nth term

eg. find the nth term of 5, 7, 10, 14, 19 ........

remembering that the nth term is given by:

        1st term, 'a' =5

        first difference 'd' = 2

        difference increase 'c' = 1

replace and see what u get

i will only rely on my brain for this one

[Saavya]

thanks alot!!! thats really helpful!!

ur welcome

[Saavya]

no actualy this is used whn there is a common difference!!
otherwise u hv to find someother way 2 do it

the other way is to use yer brain im goin 2 do that for the changing difference ones