![[Graphics:Images/index_gr_1.gif]](Images/index_gr_1.gif)
Sum by converting to a difference equation and solving that difference equation:
Express as a sum of falling factorials.
Use this result to find:
![[Graphics:Images/index_gr_4.gif]](Images/index_gr_4.gif)
Sum by parts:
Find the difference (with respect to n- 1 point each)
a)
![[Graphics:Images/index_gr_9.gif]](Images/index_gr_9.gif)
b) n!
![[Graphics:Images/index_gr_11.gif]](Images/index_gr_11.gif)
Not what I was expecting, but correct.
(n+1)! - n ! =
(n+1) n! - n! = n n!
c)
![[Graphics:Images/index_gr_14.gif]](Images/index_gr_14.gif)
d)
![[Graphics:Images/index_gr_17.gif]](Images/index_gr_17.gif)
Since =
+
, we get
for the difference.
Find an anti -difference: (with respect to n - 2 points each)
e) n(n!)
![[Graphics:Images/index_gr_23.gif]](Images/index_gr_23.gif)
f)