Mathematics: Post your doubts here!

[$~SauD~$]

solve these questions
inequality (x+1)/(x-1) <4
find stationary point y=2x^2 + e^-x^4 .....y=x^n-lnx^n for n>= 1
solve the integration of 1/2x dx
plz explain

(x+1) < 4(x-1) ==> x+1 < 4x - 4 ==> +1 + 4 < 4x -x ==> 5< 3x so x > 5/3

dy/dx = 4x - e^-x WAit what? :s e^-x^4? da fuq is this? :s

1/2x dx ==> ~ is integration sign for example..

~ 1/2x dx ==> differentiation of 2x is 2.. so numerator should be 2..
1/2 ~ 2/2x dx

1/2 ln 2x + c

 

[saadgujjar]

(x+1) < 4(x-1) ==> x+1 < 4x - 4 ==> +1 + 4 < 4x -x ==> 5< 3x so x > 5/3

dy/dx = 4x - e^-x WAit what? :s e^-x^4? da fuq is this? :s

1/2x dx ==> ~ is integration sign for example..

~ 1/2x dx ==> differentiation of 2x is 2.. so numerator should be 2..
1/2 ~ 2/2x dx

1/2 ln 2x + c

power of e is -x raise to power 4.......plz explain this question and the integration

 

[$~SauD~$]

power of e is -x raise to power 4.......plz explain this question and the integration

what kind of question is that
anyways.. it be like

- 4x^3 x e^-x^4 will differentiation of that thing and equate the whole differentiation to dy/dx = 0 and you will get staionary poitn

 

[saadgujjar]

what kind of question is that
anyways.. it be like

- 4x^3 x e^-x^4 will differentiation of that thing and equate the whole differentiation to dy/dx = 0 and you will get staionary poitn

plz solve....

 

[rawaaaan]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w11_qp_11.pdf
please answer this last question ,question 11) iii) state the domain ,someone please answer this simple one

 

[mynameisjh]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_w10_qp_63.pdf
please help me with 6(iii), permutation, stuck with it for an hr already still cant seem to solve it

 

[stubborn angel]

HI......
can anyone tellme is there core mathematicz in as n a levelz ??

 

[Anika Raisa]

PPL wid Statistics in A levels pls post ur probs here: https://www.xtremepapers.com/commun...ics-doubt-post-your-doubts-here.25911/page-19

Btwn u may find ur queries already answered there by others in prev discussions 2. BOL!

 

[immie.rose]

Need help with this asap, pls! Anyone?
Solve the equation 3^x+2 = 3^x + 3^2 , giving your answer correct to 3 significant figures.

 

[Rutzaba]

Need help with this asap, pls! Anyone?
Solve the equation 3^x+2 = 3^x + 3^2 , giving your answer correct to 3 significant figures.

is this 3 ki power x+2 or 3^x +2 ?

 

[immie.rose]

is this 3 ki power x+2 or 3^x +2 ?

its 3^(x+2). Your former guess.

 

[Soubia Sabrin]

Anyone appearing for P62 this time!???? I am bit worried, since i donot do well in statistics! Any suggestions for me?

 

[Rutzaba]

its 3^(x+2). Your former guess.

see
3^(x+2) = 3^x + 3^2
by log property u can replace powers as coefficients such that if
a^b then it can convert to b lna
so this will become...
(x+2) ln 3 = x ln3 + 2 ln3
we also know that if two ln functions are adding they will multiply
such that lna + lnb = ln (ab)
so we get
(x+2) ln3 = (2x) (ln3)
remove ln3 on both sides
2x= x+2
x=2
Hope thats the correct answer...

 

[Rutzaba]

Anyone appearing for P62 this time!???? I am bit worried, since i donot do well in statistics! Any suggestions for me?

practice?

 

[Rutzaba]

Anyone appearing for P62 this time!???? I am bit worried, since i donot do well in statistics! Any suggestions for me?

https://www.xtremepapers.com/community/threads/statistics-s1.30100/
https://www.xtremepapers.com/community/threads/a-level-statistics-doubt-post-your-doubts-here.25911/

 

[SudhaPS]

9707/61/O/N/11 Qn 5 .. Pl help.

 

[Rutzaba]

9707/61/O/N/11 Qn 5 .. Pl help.

link plz

 

[KZW]

9707/61/O/N/11 Qn 5 .. Pl help.

I'm going to assume you meant 9709 for Math.

Anyway, draw out the normal distribution graph, with lines showing
- 20(the mean) in the middle
- 12 either side of the mean, specified in the question (8 and 32)

The area in between, P(8<X<32) is 94%. So far so good?
So now you'll want to find P(X<32). Since its symmetrical, (look at the normal graph that you drew). P(X<32) = 0.5(1 - 0.94) + 0.94 = 0.97 (97%).

Convert 0.97 to its Z value, which is 1.881.
Since Z= (x-u)/sd , we can equate 1.881= (32-20)/sd

Rearrange and it should give sd=6.38

I hope that helped, good luck for the stats paper tomorrow!

 

[mnotanerd]

1 It is known that, on average, 2 people in 5 in a certain country are overweight. A random sample of
400 people is chosen. Using a suitable approximation, find the probability that fewer than 165 people
in the sample are overweight.
A box contains 300 discs of different colours. There are 100 pink discs, 100 blue discs and 100 orange
discs. The discs of each colour are numbered from 0 to 99. Five discs are selected at random, one at
a time, with replacement. Find
(i) the probability that no orange discs are selected, [1]
(ii) the probability that exactly 2 discs with numbers ending in a 6 are selected, [3]
(iii) the probability that exactly 2 orange discs with numbers ending in a 6 are selected, [2]
(iv) the mean and variance of the number of pink discs selected.

please help me with these questions​

 

[cool Asviva]

Need help with this asap, pls! Anyone?
Solve the equation 3^x+2 = 3^x + 3^2 , giving your answer correct to 3 significant figures.

is answer x=0.107 ?