Question

if the first term and common ratio of a G.P are 1 and 3 respectively ,then find the sum of it's third and fifth term​

Answer 1

Solution

Given:-

• first terms og G.P.(a) = 1
• Common ratio of G.P.(r) = 3

Find :-

• Sum of third & fifth terms of G.P.

Explanation

First , calculate Third terms

Using Formula

★ Tn = ar^(n - 1)

So, for third terms

Where,

• a = 1
• r = 3

==> T3 = 1.3^(3-1)

==> T3 = 3²

==> T3 = 9

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For fifth terms

==> T5 = 1.3^(5-1)

==> T5 = 3⁴

==> T5 = 243

Now, Calculate sum of third & fifth terms

==> T3 + T5 = 9 + 243

==> T3 + T5 = 252

Hence

• Sum of Third & Fifth terms of G.P. will be = 252

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