IGCSE MATHS Doubts

[Vin]

i need sequence formulas as wel
Thanks  alot 

s= a + (n - 1) d

d = common difference lik 2, 2, 2, ..
a = first term of sequence

..

[Malak]

can anyone tell how to find the invariant line?

[Vin]

can any1 plz help me wid m/j 2001 q8c
i can not find in my pastpapers

i cant find the paper either ..

[bulono]

i don't have that is my pastpaper...

[Saavya]

help for sequences

Changing difference sequence formula

a + (n-1)d + 0.5(n-1)(n-2)C

Where -
a = the first term
d = the first difference
C = The difference increase.

an example of its use-
sequence: 3, 5, 9, 15, 24, ...

a + (n-1)d + 0.5(n-1)(n-2)C
3 + (n-1)2 + 0.5(n-1)(n-2)2
3 + 2n - 2 + n2 - 2n - n + 2

= 3 + n2 - n

Proof, by finding the 4th term:

3 + n2 - n
3 + 16 - 4

[Vin]

can anyone tell how to find the invariant line?

check the attachment ..

[Dr.virus007™]

right sorry
where c is the difference increase

R these two diff. formulas! ! !..........when do v use the first 1....nd when is the 2nd used...!!

[ksitna]

for the invariaant line

well u have to count a certain point
like choose a point and the scale factor u would be given

so if scale factor was 2

and for example in stretch
count how far it is
then for the object
u count how far as well
and when u find a line that satisfies them like if the furthest one was 10
and the object was 5
then that would be the invariant line
hope u got it

[princess12]

at which time ur paper will begin for tomorrow maths paper 4

[haris94]

URGWNT help needed M/J 2004 question 2 c

x²-x-3=6-x³/3
3x²-3x-9=18-x³
x²+3x²-3x-27=0

[bulono]

help needed M/J 2004 question 2 c.....mine is 11 00 am GMT 3+

[$H00t!N& $t@r]

for b) there is a way to draw 3 equal lines i knew it .. cant remember!! we dont hav it in the portion .. and also i dont think we hav the remaining .. dont bother urself solving old paper .. i can give u the answer but it'll take time .. i cant even find the  book were i hav all types of geometrical rules and stuff (for engineering not fo us)   im sure nothing like this will come !! know locus n stuff ..

damn ur good!!! Thanks alot, nt just fr this question but generally! as in ur genius man! hats off!!

[haris94]

help needed M/J 2004 question 2 c.....mine is 11 00 am GMT 3+

scroll up....same page
i hv written it

[Vin]

Could someone take a look at 0580/03 Oct/Nov 2009 Paper 3 core

Question 4 part c.  "Use trigonometry to calculate the length of BC".

I did:

7 (cos 55)

Which obvioulsy isn't right as that would mean the hym is the shortest side

Where have i gone wrong please?!

Thank You!

Sin x =  opposite
          ---------
         hypotenuse  

tan x = opposite
         ----------
          adjacent

cos x = adjacent
          ---------
          hypotenuse

check this website ..

http://www.mathsisfun.com/sine-cosine-tangent.html

regarding ur sum ..

use sine
sin x =  opposite
          ---------
         hypotenuse

angle is given, name unknown as z

sin 35 = 7/z

z = 7/sin 35

 z = 12.2 cm

LEARN THE TRIGONOMETRY FUNCTIONS !!!

[bulono]

thank u haris94