Prove that, if 9 is added to the sum of first few terms of
the arithmetic sequence: 16, 24, 32, ...........gives a
perfect square?
Answers
Answered by
39
Step-by-step explanation:
Step-by-step explanation:
16,24,32,,................
here a=16,d=8
so
Sn=n/2(2*16+(n-1)8)
=n/2(32 +8n-8)
=n/2(8n+24)
Sn=n(4n+12)=4n²+12n
Adding 9 both sides
Sn+9=4n²+12n+9
=(2n)²+2*2n*3+(3)²
Sn+9=(2n+3)²
hence Sn+9 is a perfect square
hence proved
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Answered by
4
16,24,32,,................
here a=16,d=8
so
Sn=n/2(2*16+(n-1)8)
=n/2(32 +8n-8)
=n/2(8n+24)
Sn=n(4n+12)=4n²+12n
Adding 9 both sides
Sn+9=4n²+12n+9
=(2n)²+2*2n*3+(3)²
Sn+9=(2n+3)²
hence Sn+9 is a perfect square
hence proved
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