Fermi
·
Concept Library
·
Courses
·
Books
·
Problems
·
Simulations
·
Math Wiki
·
High School
Fermi
›
Problems
Mathematics
Mathematics
Problem
Show that
a
1
,
a
2
,
…
,
a
n
,
…
a_1, a_2, \dots, a_n, \dots
a
1
,
a
2
,
…
,
a
n
,
…
form an AP where
a
n
a_n
a
n
is defined as below. Also find the sum of the first 15 terms in each case. a.
a
n
=
3
+
4
n
a_n = 3 + 4n
a
n
=
3
+
4
n
b.
a
n
=
9
−
5
n
a_n = 9 - 5n
a
n
=
9
−
5
n
Browse the problem library