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Mathematics: Post your doubts here!

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

how can we solve the last question in paper4 about Sequence?
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Assalamoalikum!!
Look ....Sequence seems to be hard but actually if u use a little bit of ur brain :p u will surely find it easy!!Believe me!!Just look at the question ....the first few parts are easy and the next part which u will find hard ...will be based on these easy parts that is a combination of those answers or there will be some relation which varies according to the question!!
Eg.if u r given a table with first four columns like n=1 ....to ....n=4 and then u wil have a column for n
this table will have info abt three sequences and u will have to find the nth term!!now the first two will be simple one ...like some addition or multiplication which u can do by the rules or formulas u have...however for finding the third one u will have a problem...but if u look carefully u will find that there may be some relation with the first two sequences...may be multiplying the first two gives the third one or adding them may give the third one ...so what ever it is u will find nth term in the same way like suppose the first two are multiplied togethr to give the third one so to find the nth term for the third one u multiply the nth terms of the first two!!That simple.... :)
So this was smthng complicated ...other type is usually nt that hard!!If stuck at any question...i'll be glad to help...so plz don't hesitate!!
Hope this helps !!
Jazak ALlah Khair!!
 
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Re: IGCSE Maths Tips..nov.2009!Available..ask as u like.. :)

can you tell me how to find matrix for stretch and shear
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Assalamoalaikum!!

maths maldives said:
can you tell me how to find matrix for stretch and shear

yeah sure!!
The matrix for shear: s.f takes place of zero if invariant line is x axis then change will be in the column for y coordinate in the unit matrix and vice versa.same for shear but s.f will take place of 1
2 remember this just remember if we arrange shear & stretch alphabetically shear comes first & even 0 comes before 1 so relation of zero and shear ;)

Formula for shear factor => dist. point moves due to shear/dist. of that point from invariant line

dist. point moves due to shear : always move from object to image now see if it is +ve or -ve (+ve is up or right movement and -ve is down or left movement)

dist. of that point from invariant line:always move from invariant line to the point now check whether its positive or negative then use calc. to find out final ans. putting signs appropriately

The same applies for stretch dont forget to go from invariant line to point

Hope u got it :) Do not hesitate to ask more questions!!
 
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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

can someone please help me with may/june 2008
question number 2) c) iii)
paper 4

thank you
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Assalamoalaikum!!!
I will surely help u :)
now what u have to do is substitute the given m and n values in the eqn. y = m² − 4n²
Given m = 2x + 3 and n = x − 1
y = m² − 4n²
y = (2x + 3)² - 4 [(x − 1)² ]
Take the square....recall (a +b)² = a² + 2ab + b²
so.... y = 4x² + 12x + 9 - 4 [ x² - 2x +1]
y= 4x² + 12x +9 - 4x² +8x - 4
y = 20x + 5


That's all :)
If any confusion...pls don't hesitate !!!!
 
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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Math_angel said:
Assalamoalaikum!!!
I will surely help u :)
now what u have to do is substitute the given m and n values in the eqn. y = m² − 4n²
Given m = 2x + 3 and n = x − 1
y = m² − 4n²
y = (2x + 3)² - 4 [(x − 1)² ]
Take the square....recall (a +b)² = a² + 2ab + b²
so.... y = 4x² + 12x + 9 - 4 [ x² - 2x +1]
y= 4x² + 12x +9 - 4x² +8x - 4
y = 20x + 5


That's all :)
If any confusion...pls don't hesitate !!!!

walaikum salam .. thanks so much !!

can u also help me with question 7 of the same paper?
part a)ii) i cant find z
and parts iii) and iv)

please help if u can.
thank you
 
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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

and 10) d) please .. may/june 2008 paper 4 ..
pleas please pleeeaaassee
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Assalamoalaikum!!
Yeah so i will first tell abt Q.7Since ABCD is a cyclic quadrilateral ...opposites sides will be supplementary....so y is 180 - (x + y) ..... my answers for x is 40and y is 25 so z is 115 for me...actually for this particular question there are 3 diff.answers since solving in diffeerent methods give diff. answers!!

(iii) since tangents and radius at a point are perpendicular....angle OCT is 90 degrees!!
(iv)since central angle is double the inscribed angle of the same arc ... AOC will be 2 y ...depending on ur z value..calculate ...i have z as 115 so AOC is 230!!


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10 d (i) if u notice the values for the 2 given grids is 4 so that means for any n x n grid (i − x) − (g − c) = 4 !!
For (ii) u have to look for som esequence ...how the values differ for the grids given!! u will have the answers x + 2n and x + 2+ 2n
for the last part just substitute the values u got in (ii) and the final ans. will be 4n .... one simpler way is u can look for the sequence...looking at the sol. to other 2 grids!!
 
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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

i have a serious question that is annoying me like a bug, in the syllabus it says knowledge of the compound intrest is not needed and until now i've seen like 5 questions where it says calculate the compound intrest of an amount of money while giving the rate. But offcourse the equation is not given in the question :evil: and the thing that pisses me off more is that i've tried searching the internet for an equation and every site i go to gives me different and fairly complicated equations..
please help me out of my misery if u can :)
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Assalamoalikum!!
Ok so u learn this formula...for finding amount for compound interest A = P (1 + R/100) ^n
Where,
A stands for the amount of money accruing after n year.
P stands for the principal
R stands for the rate per cent per annum
n stands for the number of years for which the
money is invested.

and then if u have to find the interest..u can use I = A - P
This is the formula u need....don't go into any complications :)
Hope u understood!!
 

Vai

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Hey! How do you find rotational symmetry? I mean, it's really confusing.. Sometimes it's just zero, but i have no idea how to come up to a conclusion. Please help, thank you. :cry:
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

A two-dimensional shape has rotational symmetry if, when rotated about a central point, it fits its outline. The number of times it fits its outline during a complete revolution is called the order of rotational symmetry.
Note:All the points shud exactly come under each other ...and the no. of times this happens is the rotational symmetry....It is 0 when it comes back to its original position without fitting its outline even once....u can even say that it is 1..but 0 is not wrong!!so like for eg if a figure given..and when i rotate it coincides once and then comes back to original...order will be 2,i.e. u will take the final position into consideration too!!
Hope its clear...otherwise let me know!! :)
 

Vai

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

So, all shapes have a rotational symmentry of 1?
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

yes Vai as MasterOfPuppets said...all shapes have a rotational symmetry of one...thanks for answering MasterOfPuppets! :)
btw...hope u r now clear with rotational symmetry..let me know if u need more! :)
 
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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

Did you hear about that paper which someone had predicted? That those questions would come.
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

for IGCSE??i havwn't heard and that's bcoz i'm nt giving the exam!! :)
 
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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

3 red discs and 2 blue discs in a bag. 2 discs chosen at random what is the probablity that the discs are red?

Explanation required please
 

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Re: IGCSE Maths Tips nov.2010!Confused!have questions?Post h

ok now see...the order of having two discs are red then red ...so dont forget to subtract since one disc will be less after u remove one!
so it's like this: (3/5 x 2/4) = 3/10
I have tried my best to avoid silly mistakes...and i hope there is no error left!
Hope u r clear with it!! :)
 
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