Permütasyon
Matematik-Dersleri
Principles of Countig
if a think can be done m1 ways,and after it has been done a second thing can be done in m2 ways,then the two things can be done in m1,m2 ways in the indicated order.In general, if teher are m1,m2,m3,m4,……,mn different ways to do n things respectively,then these n things can be done in m1,m2,m3,. mn different ways.
Counting by summation if A>B=¢(DİSJOİNT SETS) n(A<B)=n(A)+n(B)
Example1: There are 80 mathematics and 45 biology books in bookshop. in how many different ways can we buy one mathematisc books or biology book.
n(M)=80 and n(B)=45
n(m<b)= 80+45=125
Counting by product
example2 : There are 31 calasroom each containing 19 desk in a school. how many desks are there in this school?
19*31=229
example 3: There are 4 ways travelling from the city ankara to the city sivas, and there are 5 ways of travelling from city sivas to the city erzurum .inhow many different ways can we travel from the city ankara to the city erzurum stopping over at sivas.
m1=4, m2=5
m1.m2=4*5=20