If $x,\;y,\;z$ are in $G.P.$ and ${a^x} = {b^y} = {c^z}$, then
${\log _a}c = {\log _b}a$
${\log _b}a = {\log _c}b$
${\log _c}b = {\log _a}c$
None of these
Sum of infinite number of terms in $G.P.$ is $20$ and sum of their square is $100$. The common ratio of $G.P.$ is
If the sum of three terms of $G.P.$ is $19$ and product is $216$, then the common ratio of the series is
The terms of a $G.P.$ are positive. If each term is equal to the sum of two terms that follow it, then the common ratio is
If $\frac{{a + bx}}{{a - bx}} = \frac{{b + cx}}{{b - cx}} = \frac{{c + dx}}{{c - dx}},\left( {x \ne 0} \right)$ then $a$, $b$, $c$, $d$ are in
If $y = x + {x^2} + {x^3} + .......\,\infty ,\,{\rm{then}}\,\,x = $