Given that A₃=18 and A₅=2 are the 3^rd and 5^th terms in a geometric sequence, find A₁ . A) 137 B) 143 C) 154 D) 162 E) None of the above.

Question

Quizplus · Accepted Answer

In a geometric sequence, A_n = A₁ * r^(n-1). Using A₃=18 and A₅=2, we can set up the equations: A₁ * r^2 = 18 and A₁ * r^4 = 2. Dividing these gives r^2 = 1/9, so r = 1/3. Substituting back, A₁ * (1/3)^2 = 18, so A₁ = 18 * 9 = 162.

Given That A3=18 and A5=2 Are

Given That A₃=18 and A₅=2 Are