Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
Show that
∑
n
=
0
+
∞
(
n
+
1
)
z
n
=
1
(
1
−
z
)
2
\sum_{n=0}^{+\infty} (n+1)z^n = \frac{1}{(1-z)^2}
∑
n
=
0
+
∞
(
n
+
1
)
z
n
=
(
1
−
z
)
2
1
.
Browse the problem library