Question

use the binomial theoroem to find the coefficient of x^7 in the expansion of (x+1)^11

Answer 1

(11-4)C4 = 7C4

Answer 2

still confused

Answer 3

use the formula of combination
nCr = n!/{(n-r)!r!}

Answer 4

11*10*9*8/7*6*5*4*3*2*1?

Answer 5

7C3, it means n=7 and r=3
now apply of them to the formula above

Answer 6

ok

Answer 7

opss.. 7C4 i meant :)
so, n=7 and r=4

Answer 8

still confused

Answer 9

did u know about factorial

Answer 10

a little

Answer 11

what's mean of 7! ?

Answer 12

you times 7 all the way down to 1 or whatever the other one is

Answer 13

ok, so what's the result of
7!/{(7-4)!4!}

Answer 14

it similar by 7!/(3!4!)

Answer 15

7*6*5, 4*3*2*1

Answer 16

well, i hope u can undertanding this...
7! / 3!4! = (7*6*5*4!)! / (3*2*1*4!) (cancel out for 4!)
= 7*6*5 / 3*2*1 = 210/6=35

Answer 17

so is 35 my answer

Answer 18

yes

Answer 19

not right im suppose to have something than x^7

Answer 20

u have asked to find the coefficient of x^7, so the answer is 35
completely 35x^7 :P

Answer 21

it says thats not right

Answer 22

im very sure 1000000000000000^infinity %, my answer was right :P
except, u have typo in ur question

Answer 23

no my question is right

Answer 24

do u have choices

Answer 25

no

Answer 26

ahhhhhhaaaa.... damned, i have mistaken look that numbers
it should be, x^(11-4)*(1)4 = x^7
so, the coefficient of x^7 is ONE
sorry, man :o

Answer 27

ok so what whats the answer

Answer 28

wait... i think i was do mistake again

Answer 29

it should be 11C4 not 7C4
so, 11C4 = 11!/(11-4)!4! = 11!/8!4! = 11*10*9*8!/(8!*4*3*2*1) = 330
the answer is 330

Answer 30

is it clear