can anyone help me with Combinations? ive never seen anything like this.
9C1

Question

can anyone help me with Combinations? ive never seen anything like this. 
9C1

lgbasallote · Answer

$$9C1 = \frac{9!}{1!(9-1)!}$$
ever seen those before?

anonymous · Answer

never. whats the exclamation point mean?

jim_thompson5910 · Answer

Something like 

6! 

means

6! = 6*5*4*3*2*1

You take the number in front of the ! and you multiply it by every integer less than it until you get to 1

jim_thompson5910 · Answer

So 

9! = 9*8*7*6*5*4*3*2*1

jim_thompson5910 · Answer

and it's read as "9 factorial"

anonymous · Answer

wow that seems like a long process. but alright so then with the (9-1)! i would do 8!?

jim_thompson5910 · Answer

yes

jim_thompson5910 · Answer

you evaluate what's inside the parenthesis first, then find the factorial of that

jim_thompson5910 · Answer

your calculator should have a ! button to save you time

anonymous · Answer

ok, so then i guess the denominator simplifies to 1!8! . what do i do from there?

anonymous · Answer

i dont see the ! button

jim_thompson5910 · Answer

1! = 1, so that multiplies with 8! to get 1*8! = 8!

jim_thompson5910 · Answer

So 1!8! turns into just 8!

jim_thompson5910 · Answer

8! = 8*7*6*5*4*3*2*1

what kind of calculator do you have?

anonymous · Answer

ohhhh that makes sense. so then it would be 9!/8! and just do the factorial thing and divide? i have a texas instrument TI-30XIIS i think

jim_thompson5910 · Answer

yes, find the factorial of each, then divide and simplify

anonymous · Answer

thats so much easier than i thought it would be. alright, thank you very much!

jim_thompson5910 · Answer

btw, I think if you checked the "prb" button, it might be in there

jim_thompson5910 · Answer

that's where all the probability functions are

anonymous · Answer

ohh wow i just checked, its there. wonderful(:

jim_thompson5910 · Answer

the factorial, permutation and combinations should all be there

jim_thompson5910 · Answer

alright great