Question

find only Sn for the A.P. 3,5,7,9...​

Answer 1

Sn = n/2 +(2a + (n-1)d

S4 = 4/2 + (2×3+(4-1)2. (d=5-3=2

S4 = 2+(6+3×2

S4 = 2+12

S4 = 14

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Answer 2

Answer:

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Step-by-step explanation:

your answer

a=3

d=2

n=4

Sn=n/2[a+(n-1) d]

=4/2[3+(4-1) 2]

=2(3+6)

=2(18)

=36

Hey!! your answer is 36.