Maths & Physics Help

[astarmathsandphysics]

Will pm you

[astarmathsandphysics]

Another satisfied customer. My scanner saved all the scans as a 128MB file and I had still to learn to use Latex. Luckily she lives in London so I met her at a train station on my way to a student and gave her a brown envelope.

[roma]

Hello, me again! I've been a set a coursework but i will be tested on it. So i have to learn the method used in each question and i will have a test on it which will require me to use the same methods on the coursework. I was hoping you could have a look at it for me, so that i know im learning the right stuff

Thankz

[astarmathsandphysics]

Yes he it is posted here. Cant tell now am on phone

[roma]

have you looked at it yet?

[astarmathsandphysics]

Dont i tell you make a nuisance of yourself? Am asleep.

[roma]

Can you PLEASE help me then?

[roma]

Hey, i needed some help on this question.

Prove p = 0.08512 B = 0.01881 A = 0.03119 simultaneously,
20 =1/(A + B)
23 =1/(A + Be^-5p)
25.5 =1/(A + Be^-10p)

[astarmathsandphysics]

2 hours

[roma]

Any luck?

[omarsubei]

Hi my exam's in 12 hours, and I just don't get statistics. Please help with this question,

Consider the 10 data items x1, x2, ... x10. Given that Sum(x_i)  = 1341 and the standard deviation is 6.9, find the value of the mean .

The answer is:

6.9² = 1341/10 - mean²

and then the answer works out to be +/- 9.3 .

I get the method, I just don't get why they divided by 10 ?

[astarmathsandphysics]

There must be more to the question than that. Cabn you post the question?

[omarsubei]

I'm sure that's the whole question. I don't know what you mean by post it

[astarmathsandphysics]

This is an old topic . Can you you ropost to make it current?

[astarmathsandphysics]

Hey, i needed some help on this question.

Prove p = 0.08512 B = 0.01881 A = 0.03119 simultaneously,
20 =1/(A + B)
23 =1/(A + Be^-5p)
25.5 =1/(A + Be^-10p)

1)20 =1/(A + B)
2)23 =1/(A + Be^-5p)
3)25.5 =1/(A + Be^-10p)


Turn everything upside down

1/20 =(A + B)
1/23 =(A + Be^-5p)
1/25.5 =(A + Be^-10p)
top take away next onw gives B-Be^-5p=3/460 (4) and top take the third gives 5.5/510=B-Be^-10p Divide these 2 equtions by each other to give

(1-e^-5p)/(1-e^-10p)=0.604

sub x=e^-5p to give(1-x)/(1-x²)=0.604

so 1-x=0.604-0.604x²
so0.604x²-0.604x+0.396=0 Solve this and sub into 4 to find B then into 1 to find A