Mathematics: Post your doubts here!

[papajohn]

Q9 B anyone? Please explain me how to calculate area of a triangle?

The main problem I do not understand is that how do we calculate the area of the triangle ABC while it is not making any triangle??
Please help me out of this confusion

 

[DaniyalK]

View attachment 51292

The main problem I do not understand is that how do we calculate the area of the triangle ABC while it is not making any triangle??
Please help me out of this confusion

use 1/2 * BC * OA

 

[papajohn]

use 1/2 * BC * OA

Just got it..Thanks Amigo

 

[Sarosh Jameel]

PLZ someone help me with these questions !!

 

[DaniyalK]

PLZ someone help me with these questions !!

5)i) mgh = 1/2mv^2
10(0.45) = (0.5)(v^2)
v = 3 m/s
ii) 0.39 + PE = (.5)(.3)(3^3)
PE = 0.96 J
(0.3)(10)(h) = 0.96J
h = 0.32m

4)i) motion of A:
3.6sin60 - T = (0.36)(0.25)
T = 3.03N
ii) motion of B:
3.03 - (Friction + 2.4sin60) = (0.24)(0.25)
Friction = 0.892N
Friction = uR
0.892 = u* 2.4cos60
u = 0.74

 

[crazytaylorfanXD]

For question 9:

part 1)
w=x+iy
w*=x-iy
Substitue this in the equation
equate real and imaginary parts
get value of x= 2(2)^.5 and y=-2

part 2)
all drawing of circle and lines and distance :S. If you cannot calculate it,then reply below

You sir are awesome

 

[Dr Death]

When is equation
b² - 4ac
used?

 

[rachelblurr]

www.facebook.com/alvlmaths
complete solutions for Maths P1, P3, P4, P6
Still in progress but feel free to PM me questions.

 

[DaniyalK]

Q10(ii) Please anyone explain me

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s13_qp_32.pdf

n of q = (1,b,c)
Angle between 2 planes is 60
(1,b,c) . (1,1,0)/ sqrt(1 + b^2 + c^2) * sqrt2 = cos60
(1 + b)^2 = 1/4 * 2 * (1 + b^2 + c^2)
1 + 2b + b^2 = 0.5 + 0.5b^2 + 0.5c^2
0.5b^2 + 2b + 0.5 - 0.5c^2 = 0 --- eq 1

AB lies in q so its direction vector is normal to n
(1,b,c) . (3,1-1) = 0
c = 3 + b
substitute this in equation 1 and you'll get b = -4, c = -1
x -4y - z = (1, -4, -1).(2, -3, 2)
x -4y -z = 12

When is equation
b² - 4ac
used?

It's used to check how many real roots a quadratic equation has.

 

[The Sarcastic Retard]

When is equation
b² - 4ac
used?

This is known as the discriminent.
if b² - 4ac>0 the quad eqn has two distinct roots
if b² - 4ac=0 the quad eqn has one repeated roots
if b² - 4ac<0 the quad eqn has no roots.

 

[crazytaylorfanXD]

HELP NEEDED
http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s12_ms_32.pdf
QUESTION 5
MY ANSWER IS Y=X-0.5LN3
is it the same thing as the answer in the marking scheme??

 

[papajohn]

For questions 5:

First differentiate the equation in terms of x
replace dy/dx as 0
You will get the equation: 3x^2+y^2-6ax=0
From original equation make y the subject
Replace in the equation above.
You will get the value of x= (3a)^1/2

Sorry to Interrupt .. How do we elminate y2 in the equation??

 

[Dream.Eater]

How do you do this?

 

[crazytaylorfanXD]

can someone help me out in a question?
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_ms_31.pdf
question 7

 

[papajohn]

View attachment 51357

How do you do this?

1/r + 1/(r+1) + 1/(1-r)....Is this right ans.. Let me know

 

[Dream.Eater]

1/r + 1/(r+1) + 1/(1-r)....Is this right ans.. Let me know

This is the ans

 

[DaniyalK]

HELP NEEDED
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s12_ms_32.pdf
QUESTION 5
MY ANSWER IS Y=X-0.5LN3
is it the same thing as the answer in the marking scheme??

No, the answer in the scheme doesn't work if x > .54

View attachment 51357

How do you do this?

1/r(r+1)(r-1) ≡ A/r + B/(r+1) + C/(r-1)
1 = A(r+1)(r-1) + B(r)(r-1) + C(r)(r+1)
at r = 1, C = 0.5
at r = -1, B = 0.5
at r = 0, A = -1

can someone help me out in a question?
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w11_ms_31.pdf
question 7

cosAOP = cosBOP
(1,2,2).(1+2s, 2+2s, 2-2s)/3 = (3,4,0).(1+2s, 2+2s, 2-2s)/5
solve for s and you should get s = 3/8

 

[Zain Salman Dar]

Sorry to Interrupt .. How do we elminate y2 in the equation??

find y in terms of x in original equation and replace it.

 

[Gehad Mohamed]

Hello
can someone solve Question 9 in http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w13_qp_32.pdf fully please !

 

[Farhad221]

Guys i am starting a revision group for upcoming may june 2o15 exams more details herehttps://www.xtremepapers.com/community/threads/revision-group-on-facebook-or-viber-for-science-subjects-economics-business-studies.37031/