If $\log x:\log y:\log z = (y - z)\,:\,(z - x):(x - y)$ then
${x^y}.{y^z}.{z^x} = 1$
${x^x}{y^y}{z^z} = 1$
$\root x \of x \,\root y \of y \root z \of z = 1$
None of these
The number ${\log _2}7$ is
The value of $(0.16)^{\log _{2.5}\left(\frac{1}{3}+\frac{1}{3^{2}}+\frac{1}{3^{3}}+\ldots . to \infty\right)}$ is equal to
If $n = 1983!$, then the value of expression $\frac{1}{{{{\log }_2}n}} + \frac{1}{{{{\log }_3}n}} + \frac{1}{{{{\log }_4}n}} + ....... + \frac{1}{{{{\log }_{1983}}n}}$ is equal to
Let $\quad \sum \limits_{n=0}^{\infty} \frac{n^3((2 n) !)+(2 n-1)(n !)}{(n !)((2 n) !)}=a e+\frac{b}{e}+c$, where $a, b, c \in Z$ and $e=\sum \limits_{n=0}^{\infty} \frac{1}{n!}$ Then $a^2-b+c$ is equal to $................$.
Solution set of inequality ${\log _{10}}({x^2} - 2x - 2) \le 0$ is