Which of the following functions are odd?
$I. f(x)=x\left(\frac{e^x-1}{e^x+1}\right)$
$II. f(x)=k^x+k^{-x}+\cos x$
$III. f(x)=\log \left(x+\sqrt{x^2+1}\right)$

The equation $6^{x}+8^{x}=10^{x}$ has

Draw the graph of the function $f: R \rightarrow R$ defined by $f(x) = x^{3}, x \in R$.

If $f(x) = \log \left( \frac{1 + x}{1 - x} \right)$,then $f(x)$ is

For a real number $x$,let $[x]$ denote the greatest integer less than or equal to $x$,and let $\{x\} = x - [x]$. The number of solutions $x$ to the equation $[x]\{x\} = 5$ with $0 \leq x \leq 2015$ is

Number of solutions of the equation $2^x + x = 2^{\sin x} + \sin x$ in $[0, 10\pi]$ is -