if an =7n+2 find d and a11
Answers
Answered by
1
Answer:
Given S
n
=2n
2
+5n
S
n−1
=2(n−1)
2
+5(n−1)
=2(n
2
−2n+1)+5n−5
=2n
2
−4n+2+5n−5
=2n
2
+n−3
Now, t
n
=S
n
−S
n−1
=2n
2
+5n−(2n
2
+n−3)
=2n
2
+5n−2n
2
−n+3
=4n+3
Step-by-step explanation:
Answered by
1
Answer:
Step-by-step explanation:
an =7n+2 is the general equation of terms
let's find the first term a or t₁=(7×1)+2=9
let's find the second term t₂=(7×2)+2=16
so we know that common difference "d" is the difference between two consecutive terms.
so d=t₂-t₁=16-9=7
a₁₁=(7×11)+2=77+2=79
so d=7 and a₁₁=79
hope this helps
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