Mathematics: Post your doubts here!

[RoOkaYya G]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w13_qp_13.pdf

Question 8) (iii)?

someone jst asked its part (ii) on my wall today

use substitution
let (x+3x^2) be equal to u

expand (1+u)^5 using binomial formula
in the end replace u by original bracket.

 

[RoOkaYya G]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Mathematics (9709)/9709_w13_qp_13.pdf

Question 8) (iii)?

use the answer to part (ii) to make it easier

 

[Awesome12]

someone jst asked its part (ii) on my wall today

use substitution
let (x+3x^2) be equal to u

expand (1+u)^5 using binomial formula
in the end replace u by original bracket.

Thanks

 

[Awesome12]

Ok. I have done so and after I substitute (x + 3x^2), my answer is:

405 x^8

But the marking scheme's answer is 675 x^8. Why are they adding the above answer to the answer in part (ii)?

 

[Thought blocker]

RoOkaYya G you explaining or I do?

 

[RoOkaYya G]

Ok. I have done so and after I substitute (x + 3x^2), my answer is:

405 x^8

But the marking scheme's answer is 675 x^8. Why are they adding the above answer to the answer in part (ii)?

wht u did?

 

[RoOkaYya G]

RoOkaYya G you explaining or I do?

u do .-.

 

[Awesome12]

wht u did?

(1 + u) ^5

=
1 + 5u + 10u^2 + 10 u^3 + 5u^4 + u^5


5u^4 = 5 (x + 3x^2)^4


5(81x^8)

405 x^8

 

[Thought blocker]

Ok. I have done so and after I substitute (x + 3x^2), my answer is:

405 x^8

But the marking scheme's answer is 675 x^8. Why are they adding the above answer to the answer in part (ii)?

405x^8 + 270x^8 kia?

 

[RoOkaYya G]

405x^8 + 270x^8 kia?

idiot thts wht he asked..tht y we add 270

 

[RoOkaYya G]

Awesome12 we add the 270 because it represents the coefficient of x^8
for expansion in part (iii) the expansion isnt complete i mean not all x^8 r included.
so u take the one from part (ii) also

 

[Thought blocker]

idiot thts wht he asked..tht y we add 270

This was not what he asked.

 

[Thought blocker]

Awesome12 we add the 270 because it represents the coefficient of x^8
for expansion in part (iii) the expansion isnt complete i mean not all x^8 r included.
so u take the one from part (ii) also

That was easily been understand by looking at solution of part ii :/

 

[RoOkaYya G]

This was not what he asked.

-_- he said he dint understand y they add the answer to part (ii) -_- read well

 

[RoOkaYya G]

That was easily been understand by looking at solution of part ii :/

wht u mean?

 

[Thought blocker]

-_- he said he dint understand y they add the answer to part (ii) -_- read well

My bad .-.

 

[Thought blocker]

wht u mean?

Nothing. Its better I keep shut. .-.

 

[Math Buddy]

Thanks again. BTW, I did my AS level in May/June 2014 session and scored "a". Based on what I calculated, the minimum score I got is 110. But I was just wondering what are my chances of scoring A* in A levels.

My school said if you get an A grade in As level maths, and if you maintain that A in your A level, then your A grade in A level and As level will become an overall A* so yeah you have a good chance

 

[neha saleem]

http://papers.xtremepapers.com/CIE/...AS Level/Mathematics (9709)/9709_s06_qp_3.pdf

q3 sum1 pls help..........specially dy/dthetha and dy/dx..........i kind of did it..........but i m so cnfusd at the dy/dx........i differnttd bt wat we do aftr tht?

 

[me_lonelyboy]

I cannot get the pic of the question. But figuring from the markscheme there is some mistake. Simplifying with surd rules it should be 10 cbrt(7.1) hence x can be 0.1. Upload the question again dude.

Ah. So it should be 7.1 huh.
Ok, here is the question. Again.