Using Pascal's triangle
Number of terms Expression
1 = 1----------------------------
2 = 1 1----------------------------(x+a)
3 = 1 2 1-----------
4= 1 3 3 1----------
5= 1 4 6 4 1----------
6= 1 5 10 10 5 1----------
7= 1 6 15 <u>20 </u> 15 6 1 ----------
8= 1 7 21 35 35 21 7 1 ----------
The meaning of
, is coefficient of fourth term of an expression having 7 terms.
Using pascal Triangle value or coefficient of Fourth term of the expression