Mathematics: Post your doubts here!

[sitooon]

thanks, brother.

Welcome

 

[saif mahmoud]

Simple,
To remove modulus sign, square both the sides
you get,
(x^2 + 4x + 4) > (1/4x^2 - 2x +4)
Solve equation, you get:¬
3/4x^2 + 6x = 0
One root is -8 and other is 0
so -8 is -ve, x < 8 and x > 0

ohh!!!!!
whats that lol im taking about igcse ol 0580

 

[saif mahmoud]

seems that i posted in the wrong thread

 

[Thought blocker]

seems that i posted in the wrong thread

IGCSE answer:
Total time 8 hours 30 minutes + first journey of 15 minutes that is total of 525 minutes.
So, bus leave port every 15 minutes, so in 525 minutes how many times did bus leave the port ? (do cross multiplication) that will end up to 525/15 = 35 times.

 

[saif mahmoud]

Great (Y)

 

[Haya Ahmed]

Can someone help me please
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w10_qp_13.pdf

Q7(i)

 

[MiniSacBall]

Co-efficient of x in 1/x ,2/x, 12/x
And
http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_w05_qp_1.pdf
Q9 (ii) & (iii)

 

[Talha Khatri]

Can someone help me please
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w10_qp_13.pdf

Q7(i)

We can see from the graph that it is quiet obvious that for the minimum possible value of the function, x=0
hence,
f(x) = 0.5 x^2 = 0.5 (0)^2 = 0

and for the maximum value of the function, x = 6
hence,
f(x) = 0.5 x + 1 = 0.5 (6) +1 = 4
so the range is 0 < f(x) < 6
The trick here is to use the right formula for the right value of x like for x= 0 you will use the first formula and for x= 6 you'll use the second one because they provided you with a domain that is to be used for each formula which is 0 to 2 for first and 2 to 6 for second.

 

[Haya Ahmed]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w10_qp_13.pdf

Q8ii please

 

[Haya Ahmed]

We can see from the graph that it is quiet obvious that for the minimum possible value of the function, x=0
hence,
f(x) = 0.5 x^2 = 0.5 (0)^2 = 0

and for the maximum value of the function, x = 6
hence,
f(x) = 0.5 x + 1 = 0.5 (6) +1 = 4
so the range is 0 < f(x) < 6
The trick here is to use the right formula for the right value of x like for x= 0 you will use the first formula and for x= 6 you'll use the second one because they provided you with a domain that is to be used for each formula which is 0 to 2 for first and 2 to 6 for second.

Ohh thanks bro

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w10_qp_13.pdf

Q8ii please

Find the total length from AC using sin rule
sin(1.2)/AC=sin(0.6)/5
AC=8.25
we know PC and AQ are 5 cm so
10-8.25=1.75
there is another way given in the MS but i prefer this way

 

[kitkat <3 :P]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w12_qp_12.pdf
Q1 ii) and Q7 please
m not good with vectors

 

[sudeep1097]

Thanks soo much bro ,
Got a doubt, why direction vector is
( 1'0'0) why the 1 is it alwaya 1 when
Parallel to x-axis?
When i squared both sides, didnt get
X=y
Thanks again

Sorry about the x=y .
|z-3|=|z-3i|
now removing modulus sign we get sq rt of ((real component)^2+(imaginary component)^2) on both sides
suppose z as x+yi you get sq rt of ((x-3^2)+y^2)=(x^2+(y-3)^2)
remove sq rt by squaring both sides now solve to get x=y

yeah vector parallel to x axis is always (1,0,0) for y axis (0,1,0) and z axis (0,0,1) remember this
as (1,0,0) lies in x-axis and line which lies on a bigger line is parallel to it. These are the most simple vectors parallel to respective axis, there are others as well but use this !

 

[Snowysangel]

you dont do it separately

So well get the same answer if we find the area collectively? Doesn't the negative sign reduce the total area?

 

[xyn1123]

9709/31/o/n/13
Help!

 

[Rutzaba]

So well get the same answer if we find the area collectively? Doesn't the negative sign reduce the total area?

no

 

[Faaiz Haque]

Q1)? http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s07_qp_1.pdf
I don't get it, someone please help.

 

[SitiPutri]

Q1)? http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s07_qp_1.pdf
I don't get it, someone please help.

y = 2x + c and y^2 = 4x
x = (y-c)/2 and x = y^2/4

Since the line is a tangent to the curve, then (y-c)/2 = y^2/4. And then you'll get 2y^2 - 4y + 4c.
Their discriminant must be equal to zero.
Thus, 16 - 32c = 0 -> c = 16/32 -> c = 1/2

 

[Faaiz Haque]

y = 2x + c and y^2 = 4x
x = (y-c)/2 and x = y^2/4

Since the line is a tangent to the curve, then (y-c)/2 = y^2/4. And then you'll get 2y^2 - 4y + 4c.
Their discriminant must be equal to zero.
Thus, 16 - 32c = 0 -> c = 16/32 -> c = 1/2

Thanks so much, that was very helpful.

I also need help in the same paper, question 3.
http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s07_qp_1.pdf

 

[Talha Khatri]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w12_qp_12.pdf
Q1 ii) and Q7 please
m not good with vectors

Question 1 doesn't have a part 2 and here's question 7: