Annoying Maths Questions

[SuperXDE]

I will be brief and get in the topic

Make x the subject of the formula
ax^2 + bx^2 - d^2 = p^2

EDIT : Nevermind about the above one , -.- I didn't look to the factorising of the first two terms ... solved now

But still the Loci is making me crazy !!!

Thanks in advance~!

UPDATE : http://www.xtremepapers.net/CIE/ind...SE/0580 - Mathematics/&file=0580_s07_qp_2.pdf7 ,

Questions , 3 , 10 , 16 , 17 , 20 , The Markscheme is completely ... useless to improve the likes of me.

Q3 : Xsara throws a ball three times at a target.
Each time she throws the ball, the probability that she hits the target is 0.2.
Calculate the probability that she does not hit the target in any of the three throws.

Q10 : Write as a fraction in its simplest form

x-3/4 + 4/x-3

Q16 : The function f(x) is given by
f(x) = 3x – 1.
Find, in its simplest form,
(a) f^−1×f(x),
(b) ff(x).

Q17 :
(a) sqrt(32) = 2^p. Find the value of p.
(b)crt(1/8) = 2^q. Find the value of q.

Q20 : which I call the nightmare of Locus ( sounds like an insect . . . I love geometry though .. )

Go to the PDF file for more details

The diagram shows a map of part of a coastline.
1 centimetre represents 40 metres.
(a) A ferry leaves a port P and travels between two islands so that it is always equidistant
from A and B.
Using a straight edge and compasses only, draw this locus. ( constructing a bisecting line on AB )
(b) For safety reasons the ferry must be at least 120 metres from a ship at D.
Draw the locus of the points which form the boundary of safety around D. ( a 3cm radius circle )
(c) When the ferry is 120 metres from D it must change direction.
How far is the ferry from the port P then? ( Just how in the markscheme it is ... another solution?! )

 

[larina]

ax^2 + bx^2 - d^2= p^2

ax^2 + bx^2 = p^2 + d^2

x^2(a+b) = p^2 + d^2

x^2 = (p^2 +d^2)/(a+b)

x= square root(p^2 + d^2) /(a+b)

 

[SuperXDE]

Thank you very much larina ,that clarified , however there are new updates in the main post and the Paper 2 Exam is after tomorrow , Haha... what a Careless guy I am.

 

[Pierre Samy]

will for Q3
you will have to make tree diagram ( hope u know how to do)
with each branch having 2 possibity hit =(0.2) and unpossilbe hit =( 0.8) {1-0.2}
and so u will make 3 double brachnces connected to each other in serial
then labell each branch with it function ( hit or doesnt hit )
multiplay all the doesnt hit togther you will get the answeer

 

[Pierre Samy]

about Q10
your quesion is wrong
(x-{3/4})+(4/{x-3})
answeer is like this
=[x-3{x-3}+4*4] / 4(x-3)
=[x^2-6x+9+16] / 47(x-3)
=x^2-6x+25 ( thats the final answeer
hope u got it though i am not a godd users of symbols

 

[Pierre Samy]

Q17
(A)for easily sured way to answeer such question use ur calculator function LOG =2.5
log5.656 / log2
(B) Log0.5( vlaus of 1/8 cube root ) / log 2 =-1

 

[Pierre Samy]

Q20
hard to expalin by chating but here is wut i can tell you
(a) use ur compase and measure out 5cm ( which is the quidistance) place the needle on P then move it in a semi circle shape until it is touched by the 2 points A and B draw and staright line joining both A and B together
(B) divid 120/40 ( the map scale) measure out the distance given by the clulator in the compas
place the compas's needle on D the drw and circle ( keep in mind it shouldnt get out of the diagram so it will be semi circle )
hope it help
and please need more help about physics paper 6 measuring error

 

[Pierre Samy]

will i need help in the same exam but
in the very first full Question

 

[Pierre Samy]

people i thinkg i desve help in this little question
also the function question
The function f(x) is given by
f(x) = 3x – 1.
Find, in its simplest form,
(a) f^−1×f(x),
(b) ff(x).

 

[Giraffe195]

a. y = 3x - 1
y+1 = 3x
y + 1 / 3 = X
F^-1 = x+1 /3
b. 3(3x-1) - 1
9x - 3 - 1
9x -4

 

[Giraffe195]

As for question 3. you just do
The probability of missing gaining 3 times.
0.8 * 0.8 * 0.8

It should give you the answer.

If you need help with the other questions, post here.. I think the above posters answered most of them.