sn=2n+1 find d and a8
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Answered by
1
S1=3=a
S2=5
a2=s2-s1=5-3=2
d= a2-a1=2-3=-1
a8=a+7d=3+7*-1=-4
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S2=5
a2=s2-s1=5-3=2
d= a2-a1=2-3=-1
a8=a+7d=3+7*-1=-4
mark as brainleist
ananya3892:
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Answered by
1
Given,
Sn=2n+1
To find,
d and a8
ATQ,
an=Sn-Sn-1
a8=S8-S7
Now,
Sn=2n+1
S8=2*8+1=17
S7=2*7+1=15
a8=17-15=2
Now,
S1=a1=2*1+1=3
S2=a1+a2=2*2+1=5
a2=S2-S1=5-3=2
Now,
d=2-3=-1
Hope this helps you!
Sn=2n+1
To find,
d and a8
ATQ,
an=Sn-Sn-1
a8=S8-S7
Now,
Sn=2n+1
S8=2*8+1=17
S7=2*7+1=15
a8=17-15=2
Now,
S1=a1=2*1+1=3
S2=a1+a2=2*2+1=5
a2=S2-S1=5-3=2
Now,
d=2-3=-1
Hope this helps you!
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