Question

I'm a goofy goober rock

請問這兩小題，第二張是我目前的思路，而第二小題算出錯的答案

Y
Ak >
1)
試求下列級數的和:
(1) 1+(1+2)+(1+2+2)+…+(1+2+27+2 +…+2°)
(2) 2X2+4 X5+6X8+ ... +66X98.
(3) 12+32 +52 +...+(2n-1)?. nlanti)(2n-1)
3 3

9.30 ③ - (2)
C
2x2 + 4x 5 +688 + m +66 +98
2n (3n-1)=an
as
7 Az-A2 x 2
4 so 28
88
+16
+28
+40
6
tiz
+12
,
a = 441
A2:20 = 4x5
A = 48 4112
A4 -88
4x22
A5 - 140
23 -13)
1584x aq - Az x 4
39.12
887=145
no
35
11
Ő
44
12
35+ m +(21-1)
tn
n(n+1)(2n+1)
14 6
+ 4 + 6 + m +(24) = 2/1 + 2 + +)
& nEntlanti)
An(n+
in+1)
3
-> 460114)/ 2n+1)
6
This - (0212041)
6
C
-30
(+1)(n-1)
I
ChiCt Ch 317
Ca = ( 3 400
(n-Chit 3-2)