• We need your support!

    We are currently struggling to cover the operational costs of Xtremepapers, as a result we might have to shut this website down. Please donate if we have helped you and help make a difference in other students' lives!
    Click here to Donate Now (View Announcement)

Mathematics: Post your doubts here!

MustafaMotani

MustafaMotani

Messages
1,321
Reaction score
490
Points
93
syed1995 yeah i think so... i just remeberd lst year when we were on xpf for more than 12 hrs and so came again.. :)
my subs are accel maths, physix, chem and eco
 
daredevil

daredevil

Messages
1,394
Reaction score
1,377
Points
173
falcon678 said:
ummm guys..... question 9 (i) n (ii)
Click to expand...
this is just how i might work through the question so just look at it and then its ur call totally.,..
well here goes:

i) if OAB is a straight line take them lines to be parellel

[ if vector a is parellel to vector b then
a=kb where k is a constant]

find out that constant here
as the j values are both given we use them and from there we can determine that OB = 2(OA)
so OA = 2i + j + k
so p=2
and unit vector will be OA/|OA|
|OA| = (4)^1/2
= 2

so unit vector in the direction of OA = i + (1/2)j + (1/2)k

i hope u got it....
will post the next part in the nxt reply because this is already looking at me like me with big round glasses a.k.a. NERD!! :p B)
 
syed1995

syed1995

Messages
1,824
Reaction score
949
Points
123
falcon678 said:
dude i tried tht...it gets realy tricky n more then the allotted worth of 3 marks....questions regarding scalar product are around 5-6 marks.....n if thtz the only way....can u please solve? thanks! :)
Click to expand...


MustafaMotani

AH YEAH.. I remember that question! It won't be solved with the dot product method.. try it .. it will blow your brains out :p and you won't be able to solve it.

One of our Add maths concepts is what is going to be used here :p

If Two Vector A and B are collinear (on the same line).. then Vector B = k(Vector A)

OA = p,1,1 OB = 4,2,p

Comparing the j coefficents ..

OB = k(OA)
2 = k(1)
k=2

now compare either of the first or last to get p... Like comparing the first one we get

OB = k(OA)
OB = k(OA)
4= 2(p)
p=2 Answer
 
daredevil

daredevil

Messages
1,394
Reaction score
1,377
Points
173
aw man falcon678 I swear wen i started typing that freaking answer urs was the last post there and now at least 3 other people have replied to ur post and answered while i was typing my fingers off :O :p no fair!! :p
 
syed1995

syed1995

Messages
1,824
Reaction score
949
Points
123
MustafaMotani said:
syed1995 yeah i think so... i just remeberd lst year when we were on xpf for more than 12 hrs and so came again.. :)
my subs are accel maths, physix, chem and eco
Click to expand...

I kinda knew you will be giving accel maths.. cuz you were a maths guru in our days:p S1, M1?

How's the preparations for Chemistry and Physics.. because I know I don't need to ask about your Maths P1 :p
 
daredevil

daredevil

Messages
1,394
Reaction score
1,377
Points
173
falcon678
in part ii find AB vector first:
AB = OB - OA
if OA is perpendicular to AB then the angle between them is 90 so :
OA . AB = 0
solve this out bcz i'm not doing it again or other people will post and post and post all the answers again :p
no really try it urself u'll b able to do it... if not then tell me :)
 
You must log in or register to reply here.
Top