1 1 1 1
3. Is the sequence 7' 5'8' 11'
· an A.P.? If it is an
A.P., then find its common difference.
Answers
Answered by
1
Step-by-step explanation:
d= 5-7= -2
d= 8-5= 3
d= 11-8 =3
- done
Answered by
1
Step-by-step explanation:
We have,
ANSWER
We have,
a =a= First term = -7=−7 and, d =d= Common difference = 5=5
a_{18} = a + (18 - 1)da
18
=a+(18−1)d [\because a_n = a + (n - 1)d][∵a
n
=a+(n−1)d]
\Longrightarrow a_{18} = a + 17d = -7 + 17 \times 5 = 78⟹a
18
=a+17d=−7+17×5=78
and the general term a_n = a + (n - 1) \times 5 = -7 + (n - 1) \times 5a
n
=a+(n−1)×5=−7+(n−1)×5
\Longrightarrow a_n = -7 + 5n - 5 = 5n - 12⟹a
n
=−7+5n−5=5n−12
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