Mathematics: Post your doubts here!

[moonangel996]

not now in a few hours

sure tyt

 

[Hadi Murtaza]

w

sure tyt

where u went from inbox ?

 

[mmmmmm]

Use the substitution u = sin 4x to find the exact value of cos^34x dx and the given range is (0 and 1/24pi)

 

[omaaaar]

[ (1 + sinx)/cosx ] + [ cosx/(1 + sinx) ]

Take L.C.M.
[ (1 + sinx)(1 + sinx) + (cosx)(cosx) ] / cosx(1 + sinx)

Expand numerator only
[ 1 + 2sinx + sin²x + cos²x ] / cosx(1 + sinx)

Now simplify (sin²x + cos²x = 1)
(1 + 2sinx + 1) / cosx(1 + sinx)

(2 + 2sinx) / cosx(1 + sinx)

Factorize numerator
2(1 + sinx) / cosx(1 + sinx)

1 + sinx cancels
2/cosx

Thanks man

 

[omaaaar]

Does anyone have notes for p1 integration chapter as the questions of integration always go above my head can't understand them at all . Your help would be appreciated

 

[omaaaar]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s09_ms_1.pdf
Why in question 2 k is greater than 2 but less than -6 explain

 

[Haya Ahmed]

Can someone help me ?

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s11_qp_11.pdf
Q8

 

[MiniSacBall]

Oh god i forgot, how to find maximum and minimum point of a function.
I would love simple details like 'find the derivative and then equal it to zero..bla bla'
To know the if the graph has maximum / minimum or both you have to find the first derivative and then something
and to know the points of those maximum and minimum you have to find second derivative and then...
I forgot and i just can't find in my text book. Text book really confuses me a lot.

Thanks in Advance!

 

[istudent]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s13_qp_31.pdf
Question number 7 part b please help

 

[ZaqZainab]

Oh god i forgot, how to find maximum and minimum point of a function.
I would love simple details like 'find the derivative and then equal it to zero..bla bla'
To know the if the graph has maximum / minimum or both you have to find the first derivative and then something
and to know the points of those maximum and minimum you have to find second derivative and then...
I forgot and i just can't find in my text book. Text book really confuses me a lot.

Thanks in Advance!

Find first derivative equate to zero get the x coordinate substitute the x coordinate in the equation given to get y coordinate
Now to know if its maximum or minimum
Find second derivative substitute the x value if the second derivative is negative then the x and y coordinates you found are maximum and vise versa

 

[Thought blocker]

psychiatrist Idk one question ZaqZainab solve 7b) 2012 mayjune variant 2, and I am bored with p1, I'll upload other two on 2nd may, I am busy with chemistry.

 

[rackstagryan]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s04_qp_3.pdf

could anyone please reply with the answer to q5 and q6

thanks in advance

 

[Musab100]

I told you if i knew the answer ! . sorry but I failed to get the correct answer I will ask for someone's help

ok no problem

 

[Hadi Murtaza]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s09_ms_1.pdf
Why in question 2 k is greater than 2 but less than -6 explain

(2 + k)² = 1

ok no problem

its solved buddy

 

[Snowysangel]

Can someone please solve this, step by step:
In a geometric progression, the second term is 9 less than the first term. The sum of the second and third terms is 30. Given that all the terms of the progression are positive, find the first term.

 

[ZaqZainab]

psychiatrist Idk one question ZaqZainab solve 7b) 2012 mayjune variant 2, and I am bored with p1, I'll upload other two on 2nd may, I am busy with chemistry.
View attachment 40486 View attachment 40487 View attachment 40488 View attachment 40489 View attachment 40490 View attachment 40491 View attachment 40492

Can someone please solve this, step by step:
In a geometric progression, the second term is 9 less than the first term. The sum of the second and third terms is 30. Given that all the terms of the progression are positive, find the first term.

in All GP the first term is a and second is ar and the third term is ar^2
as they have mentioned the sum of second and third term is 30
(ar)+(ar^2)=30
in this GP the first term is 'a' second is (a-9) and third is not given so lets just take ar^2 as its true for all
and as second term is 'ar' and also 'a-9'
ar=a-9
(ar)+(ar^2)=30
you have 2 equations
lets make a the subject and substitute it in the 2nd equation
a-ar=9
a(1-r)=9
a=9/(1-r)
not substituting
((9/(1-r))*r) + ((9/(1-r))r^2=30
(9r/(1-r))) + (9r^2/(1-r))=30
as denominators are the same
(9r+9r^2)/(1-r)=30
9r+9r^2=30-30r
9r^2 +9r +30r -30 =0
9r^2 + 39r -30=0
r=2/3 ,-5
if all terms are positive how can r be negative? so we won't take r=-5
a*(2/3) +a=9
a=27 i hope it helps

 

[Amina1]

http://papers.xtremepapers.com/CIE/...S Level/Mathematics (9709)/9709_s10_qp_11.pdf
Q1
Can you show how you solved it?

 

[kitkat <3 :P]

in All GP the first term is a and second is ar and the third term is ar^2
as they have mentioned the sum of second and third term is 30
(ar)+(ar^2)=30
in this GP the first term is 'a' second is (a-9) and third is not given so lets just take ar^2 as its true for all
and as second term is 'ar' and also 'a-9'
ar=a-9
(ar)+(ar^2)=30
you have 2 equations
lets make a the subject and substitute it in the 2nd equation
a-ar=9
a(1-r)=9
a=9/(1-r)
not substituting
((9/(1-r))*r) + ((9/(1-r))r^2=30
(9r/(1-r))) + (9r^2/(1-r))=30
as denominators are the same
(9r+9r^2)/(1-r)=30
9r+9r^2=30-30r
9r^2 +9r +30r -30 =0
9r^2 + 39r -30=0
r=2/3 ,-5
if all terms are positive how can r be negative? so we won't take r=-5
a*(2/3) +a=9
a=27 i hope it helps

Thank u I didnt know abt the ar^2 thing

 

[ZaqZainab]

Thank u I didnt know abt the ar^2 thing

data booklet

 

[ZaqZainab]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_s10_qp_11.pdf
Q1
Can you show how you solved it?

There are this formulas
this might help