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National and Regional Contests
Moldova Contests
Chisinau City MO
1949-56 Chisinau City MO
36
36
Part of
1949-56 Chisinau City MO
Problems
(1)
Chisinau MO p36 1949-56 VIII-IX sum 1+ 2q + 3q^2 +...+nq^{n-1}
Source:
3/15/2021
Calculate the sum:
1
+
2
q
+
3
q
2
+
.
.
.
+
n
q
n
ā
1
1+ 2q + 3q^2 +...+nq^{n-1}
1
+
2
q
+
3
q
2
+
...
+
n
q
n
ā
1
algebra
Sum