PAT'S BLOG :~)

Hey ya'll its Pat.
 
I will be blogging about some stuff that we learned in our pre-cal class this week. Mostly on Combinations and I will touch a little bit on Pascal's binomial theorem.
 
COMBINATIONS
 
first of all, what is the difference between PERMUTATION and COMBINATION?
 
we all learned that PERMUTATIONS are arrangements of a set of objects. The order matters and there are different formulas to solve for your permutation.
 

in COMBINATIONS however, the order does not matter. for combinations, we do not arrange the items. we just choose them.
 
the formula is.....
 
 
ncr where n = total and r = how many ou are choosing.
when you expand this formula it becomes.....          n!
                                                                        --------------
                                                                           r! (n-r)!

for example:

you have 10 teachers to pick from but you only need to choose 4 of them.
so if you plug it your formula.....

nCr = 10c4 = 210.

therefore, you have 210 combinations of teachers that you can pick. The order does not matter.

there are a few keywords that Mr. Piatek gave us for combinations:

CHOOSE
COMMITTEE
SELECT

Basically, we just have to remember that permutations are specific. Combinations are not specific.

moving on to
PASCAL'S BINOMIAL THEOREM

Yesterday in class, Mr Piatek showed us this pattern.
 

 and i foud this video that explains all the patterns that you find in the triangle!
 

....ok that's all im going to blog about for now. see you guys in class :~)