Question

nCn is __________ equal to 1.
always
sometimes
never

Answer 1

@Lunalovegood do you know how nCn is defined?

Answer 2

How many different ways can you choose 3 marbles from a bag if there are 3 marbles in the bag?

Answer 3

@SmoothMath that's a smooth answer:P

Answer 4

Ahahaha thank ye kindly.

Answer 5

no i don't @ash2326

Answer 6

Do you know what is n!
?

Answer 7

no..our teacher just kind of sprung this on us with out us knowing what it is

Answer 8

Ok, n! is defined as
\[n!=1 \times 2 \times 3 \times 4 \times 5....\times n\]
so
\[2!=1\times 2=2\]
\[3!=1\times 2 \times 3=6\]
Do you understand this?

Answer 9

yes

Answer 10

:D good, tell me what's 5! ?

Answer 11

@Lunalovegood are you trying?

Answer 12

yes

Answer 13

let me know if you get stuck, whenever you say we'll proceed with the problem

Answer 14

i'm stuck

Answer 15

Ok, did you use the definition of n! to find 5!?

Answer 16

yes,

Answer 17

Where have you got stuck?

Answer 18

ummm...well you could say like the first part

Answer 19

\[5!=1 \times 2 \times 3 \times 4 \times 5\]
or
\[4!=5\times 4 \times 3 \times 3 \times 1\]
Do you get this?

Answer 20

yes

Answer 21

Now you know
\[^A C_B =\frac{A!}{B!(A-B)!}\]
Can yo find 2C2

Answer 22

@ash2326 , I will take over .:D

Answer 23

@Lunalovegood I gotta go now. Sorry:(
My friend @shivam_bhalla will help you

Answer 24

ok

Answer 25

Ok. Yes @Lunalovegood , tell me what you got for 2C2

Answer 26

@Lunalovegood , are you there ??

Answer 27

yes

Answer 28

did you find 2C2 or are you facing any problems ??

Answer 29

yes

Answer 30

@Lunalovegood , yes for what ??

Answer 31

i' am facing problems

Answer 32

See,

\[2C_2 = { 2! \over (2-2)! 2!}\]

Now @Lunalovegood , you should know that
0! = 1

Rest you can solve. Now tell me what is 2C2 = ??

Answer 33

@Lunalovegood , still any problem ??

Answer 34

@Lunalovegood , there ??