Find the sum of first n even natural numbers and also find the sum of first 20 even natural
numbers. answer it urgently
Answers
Answered by
0
Answer:
a=2
D=2
s20 = n/2 (2a + n-1×d)
= 10 (4 + 38)
= 10 (42)
= 420
Answered by
23
Answer:
a = 2
d = 2
sn = n/2(2a + (n - 1)d)
=> n/2(4 + (n - 1)2)
=> n(2 + n - 1)
=> n^2 + n
When n = 20:
=> 400 + 20
=> 420
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