Question

Помогите решить задание 4.10

Answer 1

$\frac{a^6+a^{13}}{a^{-6}+a^{-13}} = \frac{a^6(1+a^7)}{a^{-6}(1+a^{-7})} = \frac{a^{12}(1+a^{7})}{1+a^{-7}} = \frac{a^{12}(1+a^7)}{1+\frac{1}{a^{7}}} = \frac{a^{12}(1+a^7)}{\frac{a^{7}+1}{a^{7}}} = \\\\=\frac{a^7a^{12}(1+a^7)}{a^{7}+1} = a^{7+12}=a^{19}$