# Mathematics: Post your doubts here!

Discussion in 'International A And AS Level' started by XPFMember, Sep 8, 2011.

1. ### thestudyguy

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its a sequence question so i dont think they will give marks for this
btw there is no compound interest in the AS syllabus for maths

3. ### AAnsarii

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Assalamu alaikum wa rahmatullah.
I picked up math again after a long time.

Pure Mathematics 1, by Hugh Neill and Douglas Quadling, Chapter 1, Miscellaneous exercise 1, questions 4, 20 and 22.
4. A(7,2) and C(1,4) are two vertices of a square ABCD.
a. Equation of the diagonal BD.
b. Coordinates of B and D.

For part a., I know the product of two diagonals is -1, but I can't get it
Q 20 is similar, but a rhombus.

22. Two lines have equations y=m1x+c1 and y=m2x+c2, and m1m2= -1. Prove that the lines are perpendicular.
(PS for 22, I couldn't type the 1s and 2s in subscript, sorry.)

Jazakumullahu khayr

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a)
m(AC) = (y₂ - y₁)/(x₂ - x₁)
m(AC) = (4 - 2)/(1 - 7)
m(AC) = 2/-6 = -1/3
Therefore m(BD) would be = - 1/(-1/3) = 3

The midpoints of both diagnols will be the same since they intersect.
Midpoint = (x₁ + x₂)/2 , (y₁ + y₂)/2
Midpoint = (7 + 1)/2 , (2 + 4)/2
Midpoint = (4 , 3)

Using point slope formula
y - y₁ = m(x - x₁)
y - 3 = 3(x - 4)
y - 3 = 3x - 12
[ y = 3x - 9 ]

b)
The distance from the midpoint to points B and D is the same as the distance from the midpoint to A and C.
d² = (x - 4)² + (y - 3)²
d² = (7 - 4)² + (2 - 3)²
d² = 9 + 1
d² = 10

10 = (x - 4)² + (y - 3)²
Substituting y = 3x - 9
10 = (x - 4)² +(3x - 9 - 3)²
10 = x² - 8x + 16 + 9x² - 72x + 144
10x² - 80x + 150 = 0
x² - 8x + 15 = 0
(x - 5)(x - 3) = 0
[ x = 5 , 3 ]

y = 3x - 9
y = 3(5) - 9 , 3(3) - 9
[ y = 6 , 0 ]

Hence B and D are (3 , 0) and (5 , 6)

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5. ### Jenessa182

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Hi could someone help me with this question:
Simplify the following
(n+1)!/n!

6. ### Jenessa182

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Hi, could someone help me with this question?
Use the inductive definition to find the Pascal sequences for (a)n=5 (b) n=6 (c) n=8

7. ### studyingrobot457

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will be n+1 , lets say n=3, (3+1)!=4!=24,3!=6,24/6=4

8. ### Thought blocker

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(n+1)! = (n + 1) * ( n)!
therefore the answer to this question is (n + 1)

9. ### krishnapatelzz

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10. ### NerdyBirdy

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Plz help me with this question
Find the value of the constant k for which the line y+2x=k is a tangent to the curve y=x^2-6x+14

11. ### Thought blocker

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y = k - 2x
y = x^2 - 6x + 14

Equate them

k - 2x = x^2 - 6x + 14
x^2 - 4x + 14 - k = 0

As tangent meet once to the curve we can say that D = b^2 - 4ac = 0

16 - 4(14 - k) = 0
k = 10

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There are many people taking benefits from this course, and some are there from the As and A level whats app group I mentioned above. You can persnoally ask them how they improved them selves or try yourself by just with one hour clearing concepts and then if you feel good you can continue with chapter wise and if you want you all chapters to be perfect as I teach you can also take the full course. The most benefit you get from this is YOU WILL GET 24 x 7 HELP from me, I will be solving your doubts from the chapter/concepts I taught you or had taught you before as soon as you send them apart from any technical issues I will be there to help all the time. And also solve the doubts from other chapters too but that will be solved when I will be having time. I hope to see you in my batch. Good luck.

P.s.s As and A level group is free, you can post your doubts there as much as you want admins and other people will try to help you as much as they can when they get time.

12. ### Lenin Kumar Gandhi

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Anyone has a question bank for AS and A level Pure Mathematics P1 and P3. I had the question bank in the past for 0580-Extended Mathematics. It was called Q-Kit. It was really useful. You can make worksheets 'Topic-wise' in minutes... I hope to see something like that for AS and A-levels too.....
My e-mail ID: [email protected]

13. ### sushil bista

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Does anyone has 8mundo's solved pastpapers.

14. ### aqeelZamir

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WHICH YEAR PAPER YOU NEED?

15. ### aqeelZamir

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ANY ONE HAS 9709 2017-42 Q4 SOLUTION

16. ### Holmes

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2017 June or November????
Solution means .....Marking scheme? or you want explanation.

17. ### sushil bista

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if u have all then please share it to me

18. ### Holmes

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Help me out!

19. ### Holmes

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Help me out Maths Geeks!

20. ### abbas haider

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We have 4T and 4B
all T stand next to each other and All B stand next T each other
which means we can treat 4T as 1 object = T ,and 4B as one object = B
now we have B and T (total arrangements right now are (between T and B)2 *4!(within B) * 4!(Within T ) = 2*4!*4!
but we know that 3B 's refuse to stand next to any T... and we know that there are two arrangements between groups( BT or TB)
which means that 1 B(the one who does'nt refuse = friendly person) must be facing to the T's always....thus it has 2 positions
and Rest 3Bs must be next to each other and so they will have arrangement withinthemselves ....which is 3!
2(between groups)*4!(withinT) *3! (within B's that refused) = 2*3!*4! = 288

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