find the form term of 7,3,21
Answers
Answered by
1
Given arithmetic sequence
3
,
5
,
7
,
9
,
...
...
...
,
21
The first term
a
=
3
& a common difference
d
=
5
−
3
=
7
−
5
=
⋯
=
2
If there are
n
number of terms in the above A.P. then last term
l
=
21
will be the nth term given as
l
=
a
+
(
n
−
1
)
d
21
=
3
+
(
n
−
1
)
2
n
=
10
hence the sum of given arithmetic progression (
A
.
P
.
) up to
10
terms is given general formula
S
n
=
n
2
(
a
+
l
)
S
10
=
10
2
(
3
+
21
)
=
120
This seems to be the most appropriate answer.
hope it will help you
mark.me as BRAINLIEST
Similar questions