Question

Find S↓4of the sum of the geometric series.a1=32,a4=−4,r=1−2

Answer 1

3
∑
x
=
3

−
1
x
2
∑
x
=
3
3
⁡
-
1
x
2
4
∑
x
=
0

11
x
5
∑
x
=
0
4
⁡
11
x
5
3
∑
x
=
3

2
Or

csc
(
60
)
csc
(
60
)

sin
(
330
)
sin
(
330
)
−
4
cot
(
−
45
)
-
4
cot
(
-
45
)