1,3,5 ....is an arithmetic sequence (a) find 20th term (b)sum of 20th sequence (c)sum of first 20 terms of arithmetic sequence 6,8,10
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1,3,5 ....is an A. P. (Given)
a = 1 & d = t2 - t1 = 2
(a) find 20th term
t20 = a+19d
= 1+19(2)
= 1+38
= 39
(b)sum of 20th sequence
S20 = 20/2(2a+19d)
= 10(2+38)
= 10(40)
= 400
(c)sum of first 20 terms of arithmetic sequence 6,8,10
a = 6 & d = 2
S20 = 20/2(2a+19d)
= 10(12+38)
= 10(50)
= 500
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