sum of first 9 nstural odd numbers if Sn= n×n
Answers
Answered by
1
Answer:
so is then 9×9=81
Step-by-step explanation:
sn =n/2(first term+ last term)
=9/2 ( 1+17)
= 9/2(18)
=9×9
=81
Answered by
1
Answer:
81
Step-by-step explanation:
Sn=n/2[2a+(n-1)d]
S9=9/2[2×1+(9-1)2]
S9=9/2[2+8×2]
S9=9/2[18]
S9=9 ×9
S9=81
so,answer is 81.
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