Mathematics: Post your doubts here!

[AdeelRox]

(x+3)^3=-1
3lg(x+3)=lg(-1)
;no solution as lg(-1) is not valid

dude it would be
(x+3)^3 +1=0
x+3=(-1)^(1/3)
x+3=-1
x=-4

 

[Executor]

AOA,
Can anyone provide me the formula sheet for P1 and P3?
Thanks in advance.

 

[WayneRooney10]

3^x+2=3^x+3^2. Solve for x. And do tell me how you did it.

 

[AdeelRox]

3^x+2=3^x+3^2. Solve for x. And do tell me how you did it.

dude its simple
3^(x+2) = 3^(x+3)^2
since the base i.e 3 is same therefore cancelling base on both sides we have
x+2 = (x+3)^2
x+2 = x^2 + 6x + 9
x^2 + 5x + 7 = 0
applying formula, X= b^2 'plus minus' ((b^2 - 4ac)/2a)^0.5
X= -5/2 + (i(3)^(1/2))/2 , -5/2 - (i(3)^(1/2))/2
i hope this will help and wont get much complicated

 

[yashmehta96]

Please someone try this one from 9709/32/0/N/11
Question 10 part 2nd

 

[smzimran]

This is the solution to a question asked by bamteck:

Sorry for a v.late reply

Q7 :
(i) cut the triangle in half such that it becomes a right angled triangle

now
sin@ = (99/2) / r

r = 99 / 2sin@ ....eq(1)

Using the formula
s = r@
100 = r(2@)
100 = 2@r

Substitute eq(1) in above equation
100 = 2@ (99 / 2sin@)
100sin@ = 99@
sin@ = (99/100) @

so
sin x = (99/100) x

(ii) Find out the values of
sin x - (99/100) x

for values of x = 0.1 and x = 0.5
The change in sign shows that root lies in b/w

(iii) the equation from (1) was
sin x = (99/100) x

We have to process x = 50sin x - 48.5x to form above equation
x + 48.5x = 50sin x
49.5x = 50sinx

multiply both sides by 2
99x = 100sinx
(99/100) x = sin x

Shown

(iv) Simple .... just use the iteration formula

 

[smzimran]

Another question asked by bamteck

Q8 :

(i) let root(-3 + 4i) = a + bi
the squaring both sides
-3 + 4i = a^2 + 2abi + b^2i^2

Since i^2 = -1
(-3) + (4)i = (a^2 - b^2) + (2ab)i

Real part = Real part and Imaginary part = Imaginary part
a^2 - b^2 = -3 and 2ab = 4

Solve these equations simultaneously to get values of a and b

(ii) multiply z by (2 - i) / (2 - i) [compliment of denominator of z]

and use i^2 = -1

You will get the correct answer!

 

[smzimran]

Please someone try this one from 9709/32/0/N/11
Question 10 part 2nd

Search this thread i have done this question here before , around 14-15 may!

 

[Mithrandir]

PLEASE HELP!
Find the volume of the solid formed when area under the graph y=sec1/2x is rotated 360 degrees about the x-axis, for boundaries 0 to 1/3 pi (sorry, couldn't find the symbol)
AND...
Integrate the following function:
4x-18
4x^2 + 4x-3
THANKS
P.S. please show me the method behind this madness

 

[Amy Bloom]

Can somebody help me in Differential equations, i.e, how to separate the variables with illustrations please?

 

[bamteck]

URGENT ! Someone help me to solve out this.
Its from J03/P3
Thanks

 

[smzimran]

URGENT ! Someone help me to solve out this.
Its from J03/P3
Thanks

 

[smzimran]

Can somebody help me in Differential equations, i.e, how to separate the variables with illustrations please?

Simply take y variables to L.H.S and x variables to R.H.S
Let dy be on L.H.S and dx taken to R.H.S

It is better done in practise!

 

[smzimran]

PLEASE HELP!
Find the volume of the solid formed when area under the graph y=sec1/2x is rotated 360 degrees about the x-axis, for boundaries 0 to 1/3 pi (sorry, couldn't find the symbol)
AND...
Integrate the following function:
4x-18
4x^2 + 4x-3
THANKS
P.S. please show me the method behind this madness

For second question, factorise the denominator , break usiing partial fractions and then integrate , its not difficult, just lengthy!

 

[Amy Bloom]

Thanks a lot pal! Yet, i have difficuties when inversing etc.. if u know some examples which clearly supports what u said, please post them. tnx!

Simply take y variables to L.H.S and x variables to R.H.S
Let dy be on L.H.S and dx taken to R.H.S

It is better done in practise!

 

[smzimran]

Thanks a lot pal! Yet, i have difficuties when inversing etc.. if u know some examples which clearly supports what u said, please post them. tnx!

Ask questions which u have difficulties in and i would solve !

 

[Amy Bloom]

Ask questions which u have difficulties in and i would solve !

Okay! now my internal exams are over, i have to concentrate on other subjects right now.
When i'll practice past exam papers, and if i have troubles, i shall tell you. Thanks a lot!

 

[Mithrandir]

View attachment 13765

For second question, factorise the denominator , break usiing partial fractions and then integrate , its not difficult, just lengthy!

Thanks a stack. Amazing how one stupid mistake can send you so far off track.

 

[Amy Bloom]

Thanks a stack. Amazing how one stupid mistake can send you so far off track.

Rightly said ^^

 

[parthrocks]

can someone who is a genius or knows this help me out...m stuck!!!!PURE MATHEMATICS 2 and 3 a LEVELS!!!!PLZZZ ATTACH A SCAN IF POSSIBLE.....PLZZZZZZZZZZZZZZZZZZ......YA YOU!!!