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IGCSE MATHS Doubts

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Shazizzzle:

--- Quote from: deadman786 on May 16, 2010, 02:12:28 pm ---One final thing guys. Can anyone help me with the final two parts of the last question of paper 4 Nov 09?? (If it has already been answered then just mention the page number). By the way, anyone has any ideas on how to tackle such questions??? I mean it's all fine and great through out the paper until I reach the final parts of the last question....

--- End quote ---

It's really quite simple.

In (f), In n(n+1), you replace n by (n-1), because you want the total of the first (n-1) even numbers, not n.
So, answer= n(n-1) after simplification.

In (g), look at the first line of the Q of (e).

For Row 3, (3 x 7) + 2 + 4
i.e (number of row X first number in row) + sum of first (n-1) even numbers. [row is three, however the even numbers are 2, so n-1]

Replace the nth terms in above,

[(n) x (n^2 - n - 1)] + n(n-1)
i.e [c(i) x (d)] + (f)

Simplify, and you get n^3, which is equal to c(ii).

syedz123:
guys i've realised that my only weakness in maths is sequences...its so anoying!! i jst dunno hw to deduce da formula...i dnt get it...can any1 please help explain sequence to me...By the way am stuck on question 11 D (i) p4 may/june 09...

mdwael:
IN Oct/Nov P4 2007 page 7 the last question, what does "triangle which is a plane of symmetry of the pyramid" mean? Its quesion 5 (c, (v)) part Page 7

Vin:

--- Quote from: mdwael on May 16, 2010, 03:22:10 pm ---IN Oct/Nov P4 2007 page 7 the last question, what does "triangle which is a plane of symmetry of the pyramid" mean? Its quesion 5 (c, (v)) part Page 7

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plane of symmetry is "cutting" the pyramid exactly half should be .. HPN or MPG

mdwael:

--- Quote from: ~VIN1094~ on May 16, 2010, 03:27:26 pm ---plane of symmetry is "cutting" the pyramid exactly half should be .. HPN or MPG

--- End quote ---

great I understood now but the MS says its PHN and PGM your are the same vertices so I guess they can be written any order right?

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