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Re:question

molecular orbital theory!!!s orbital is conventiaonlaly taken positive(+) sign (i mean si

molecular orbital theory

molecular orbital theory

like if compress a gas the pressure would increase cos volume decreases and the no. of particles striking the walls increases

in s solid its the inter molecular forces which transfer the pressure .

but what causes pressure in liquids ??????????

their volume des not decrease significantly .....

ya it should be an odd one
for
(2008-n)^2007-n^2007=sum of terms divisible by 2008

me too

a^n+b^n

app remainder theorem

(a+b)=0

-a=b

a^n+(-a)^n

=0

if n is odd

else

2*a^N

why inductive effect involves only sigma electrons .

like in

C--C--C=C--X

will not induction take place across (=) bond

and how?

no dear do it completely

i tried it earlier it failed

may you can do itr

i have simple

sum((-1)^r-1*nCr*1/r = sum(-1^r-1((n-1)Cr-1+(n-1)Cr)1/r

break the term

nCr=(n-1)C(r-1)+(n-1)Cr and proceed you will get ans

1/nsum(-1^r-1 (n-1)C(r-1)n/r +sum(-1^r-1n-1Cr*1/r)

it is based on fact

nCr/(n-1)C(r-1)=n/r

nCr=n*[(n-1)C(r-1)*1/r]

1/nsum((-1)^r-1nCr) +SUM(-1^r-1(n-1)Cr*1/r)

1/n+sum(-1^r-1)(n-2)Cr*1/r) + sum(-1^r-1(n-2)C(r-1)*1/r

do same thing

1/n+1/(n-1)sum(1-^r-1(n-1)Cr)+sum(-1^r-1(n-2)Cr)

1/n+1/n-1+sum.......

do it again till n step

1/n+1/n-1+1/n-2

on reversing and writing

1+1/2+1/3..........1/n................ans

edited

simple

1/(n)(n+1)(n+2)................U(n)

1/(n-1)(n)(n+1)...................U(n-1)

U(n)/U(n-1)=n-1/n+2

(n+2)U(n)=(n-1)U(n-1)

2U(n)=(n-1)U(n-1)-nU(n)

summating

2S(n)=U(1)-nU(n)

s(n)=U(1)/2 - nU(n)/2..............ans

=1/4*3 - 1/2(n+1)(n+2)

your method is not wrong but just a little

mistake

you siad that no couple come in one match

you proceeded correctly

5............men

5..............women

so no of ways

5*4

correct

for selecting second team

you chose

4 men but you forgot that the wife you selected in first team has his husband out in the group still so you can ttake that men

4-1

no you canchoose 3 men

same for the men you choose first team

his wife is out

so 4-1=3

now no of way is 3-1=2 ...........leaving the wife of hus. selected insecond team

5*4*3*2=120

but you see that teams can be interchanged

120/2=60

cheer up!!!!

your second part can be done easily

x.............female

y.................male

your ans ;

coefficient of x^2y^2

(1+x+y)^5

by multinomial theorem

5!/2!*2!

=30

now 2 ways are ppossible of making teams of 2 male and 2 female

so

30*2=60

i posted this earlier but in your other post

no of zero

will be gained just by seeing

the power of ten

and power of 2 and power of 5

in total product

let the power of 10=y

power of 2=x

power of 5=z

power of 5<power of 2

so obviosly

ans=y+z

check whether x<z

otherwise

y+x

You may not like using multinomial th to much but lately i have been fancied by its versutality

your

ans

make groups

y-------male

x--------female

(1+x+y)(1+x+y)....5times

(1+x+y)^5

(1+x)^5+5(1+x)^4y+10(1+x)^3y^2+10(1+x)^2y^3+5(1+x)y^4+y^5

coefficient of x^2y^2

= see only third term=3*10=30

in each case you have selected 2 male and two female

2 teams can be made out of four in 2 ways

so ans

=30*2=60