IGCSE/GCSE/O & A Level/IB/University Student Forum

Qualification => Subject Doubts => IGCSE/ GCSE => Math => Topic started by: Diablo on October 25, 2009, 01:23:10 pm

Title: Oct/Nov 2008 - Math
Post by: Diablo on October 25, 2009, 01:23:10 pm
Hiya!

I was always curious how would final answer look like; I solved this ages ago, but I was never sure of the answer. Can someone upload a picture of the answer? I'd appreciate it.

Thanks in advance  :D


Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 01:39:39 pm
hey that is easy
first take ur compass then mark equal distance BD then make an arc app. make a circle towards the right of B keeping the center B
then take the compass and  measure BC without moving or changing it, place the pointer(the fixed point) on C
draw the arc such that it cuts the previous one
the intersection is known as point D' (image of D)
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 01:41:35 pm
hey that is easy
first take ur compass then mark equal distance BC then make an arc app. at 900 towards right of point B
then take the compass and  measure BC without moving or changing it, place the pointer(the fixed point) on C
draw the arc such that it cuts the previous one
the intersection is known as point D' (image of D)

wat abt the locus of the points?
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 01:47:04 pm
wat abt the locus of the points?

maybe something like this
PS : the shaded region is the locus (i too am a little doubtful abt this)

EDITED : REmoved the shaded region..only a line (arc) the red line
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 01:54:28 pm
actually aadi i feel ur diagram is right
they are asking locus of B why are you shading
Locus of point B is shown by the dotted lines in my figure!!
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:02:57 pm
oops i feel some diagram error wait a sec let me configure it..
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 02:07:39 pm
actually aadi i feel ur diagram is right
they are asking locus of B why are you shading
Locus of point B is shown by the dotted lines in my figure!!


B is the origin and locus of D is asked

edited my post
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:08:38 pm
so is my answer rite or not???
i guess it is the same as yours???
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 02:09:38 pm
so is my answer rite or not???
i guess it is the same as yours???

modify it to a solid line..Locus of B aint asked...locus of D is asked...B is the origin
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:11:22 pm
so in ur diagram
the red lines are locus of D???
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 02:14:47 pm
so in ur diagram
the red lines are locus of D???

yea..the arc..
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:16:07 pm
how can the line C'D' and C'B can be locus for D???
or is it only the curve that is locus??
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 02:21:45 pm
yea..the arc..

read the latter part again..
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:22:58 pm
kk
got it
hope that diablo gets it tooo :P :P :P
Title: Re: Oct/Nov 2008 - Math
Post by: SGVaibhav on October 25, 2009, 02:35:24 pm
omg , is it solved ???
if not, i will solve it in a easy way :D
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:38:28 pm
yupp it is solved
i think so
see the diagrams aadi made it in paint
i made it on my own
and now in my diagram dotted lines is the ans
in adis the curved red line is the answer not C'D' and C'B
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 02:39:15 pm
yupp it is solved
i think so
see the diagrams aadi made it in paint
i made it on my own
and now in my diagram dotted lines is the ans
in adis the curved red line is the answer not C'D' and C'B

the dotted line shudnt be the answer...it has to be a solid line..
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:41:35 pm
k..
the dotted lines whioch shud be solid line is the answer!!!
ok!!
Title: Re: Oct/Nov 2008 - Math
Post by: holychalice on October 25, 2009, 02:45:55 pm
sumbody explain me this ... again .. in an easier manner  :P
Title: Re: Oct/Nov 2008 - Math
Post by: Ghost Of Highbury on October 25, 2009, 02:47:36 pm
sumbody explain me this ... again .. in an easier manner  :P

arre wat easier method dude...just draw the image and make an arc from D to D'...bas!

itna kya discussion chahiye//
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:50:27 pm
i guess we both are in add. math so it ias easy for us  :P :P :P :P

lolzz :D :D

no offence
Title: Re: Oct/Nov 2008 - Math
Post by: holychalice on October 25, 2009, 02:52:15 pm
well vaibhav said he cud explain in an easy way ... i was asking By the way ...
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 25, 2009, 02:53:50 pm
i guess vaibhav is still trying to find the better way to explain
i guess the only way to anwers is to make the diagram like adi and i have done
Title: Re: Oct/Nov 2008 - Math
Post by: holychalice on October 25, 2009, 02:54:50 pm
allrite ... Thanks
Title: Re: Oct/Nov 2008 - Math
Post by: SGVaibhav on October 25, 2009, 03:23:12 pm
tough luck

i had solved all igcse maths past papers paper 4 from 1998 june till 2009 oct nov, all in a book, and i had thrown away that book, now let me read it and try to solve
Title: Re: Oct/Nov 2008 - Math
Post by: @d!_†oX!© on October 25, 2009, 03:31:52 pm
sumbody explain me this ... again .. in an easier manner  :P
manbir...we've done this question in the class...don't you remember?? :o
and its not from add. maths shreycool....its from our syllabus..as in igcse maths
manbir....simply draw a line BD....
then using a D measure a 90 degrees angle at B for BD....
draw a line of the same length as BD along the 90 degree anglee...mark this point F
then draw a curve from D to F...dts the locus....
isn't that rite guys???
Title: Re: Oct/Nov 2008 - Math
Post by: SGVaibhav on October 25, 2009, 03:35:05 pm
i bloody forgot or what :S

nothing is going in my mind ???

because currently im concentrating on related rates in differnetiation

either i never did this paper 2,
or i forgot
Title: Re: Oct/Nov 2008 - Math
Post by: holychalice on October 25, 2009, 03:37:38 pm
but i din noe .. Thanks adi
Title: Re: Oct/Nov 2008 - Math
Post by: @d!_†oX!© on October 25, 2009, 03:47:37 pm
ohhkk manbir...
so now u got it????
Title: Re: Oct/Nov 2008 - Math
Post by: Diablo on October 25, 2009, 04:52:44 pm
Wow XD had no idea it would turn into a discussion :P. I actually solved it like how you guys did [ on the first page ] but for some reason I always feel doubtful about locus answers =|

Thanks a lot guys!
Title: Re: Oct/Nov 2008 - Math
Post by: ~~~~shreyapril~~~~ on October 26, 2009, 04:53:30 am
no probs mann!!
ne time