Simplify:
$(i)$ $2^{\frac{2}{3}} \cdot 2^{\frac{1}{3}}$
$(ii)$ $\left(3^{\frac{1}{5}}\right)^{4}$
$(iii)$ $\frac{7^{\frac{1}{5}}}{7^{\frac{1}{3}}}$
$(iv)$ $13^{\frac{1}{5}} \cdot 17^{\frac{1}{5}}$

To simplify these expressions,we use the laws of exponents:
$(i)$ Using the product rule $a^m \cdot a^n = a^{m+n}$:
$2^{\frac{2}{3}} \cdot 2^{\frac{1}{3}} = 2^{\left(\frac{2}{3} + \frac{1}{3}\right)} = 2^{\frac{3}{3}} = 2^1 = 2$.
$(ii)$ Using the power of a power rule $(a^m)^n = a^{m \cdot n}$:
$\left(3^{\frac{1}{5}}\right)^4 = 3^{\left(\frac{1}{5} \cdot 4\right)} = 3^{\frac{4}{5}}$.
$(iii)$ Using the quotient rule $\frac{a^m}{a^n} = a^{m-n}$:
$\frac{7^{\frac{1}{5}}}{7^{\frac{1}{3}}} = 7^{\left(\frac{1}{5} - \frac{1}{3}\right)} = 7^{\left(\frac{3-5}{15}\right)} = 7^{-\frac{2}{15}}$.
$(iv)$ Using the product rule for different bases with the same exponent $a^n \cdot b^n = (a \cdot b)^n$:
$13^{\frac{1}{5}} \cdot 17^{\frac{1}{5}} = (13 \times 17)^{\frac{1}{5}} = 221^{\frac{1}{5}}$.