Question

I)Find the first term of a G.P. whose fifth term is 243 and thecommon ratio 3.​

Answer 1

Answer:

first term = 3

Step-by-step explanation:

The n th term of a GP is

$a_{n}$ = a₁$(r)^{n-1}$

where a₁ is the first term and r the common ratio

Here r = 3 and a₅ = 243 , thus

a₁ × $3^{4}$ = 243

a₁ × 81 = 243 ( divide both sides by 81 )

a₁ = 3