Question

(p/q+q/p) ^2-(p/q-q/p)^2-2

Answer 1

$\left(\frac{p}{q}+\frac{q}{p}\right)^2-\left(\frac{p}{q}-\frac{q}{p}\right)^2-2=\left(\frac{p}{q}+\frac{q}{p}-\frac{p}{q}+\frac{q}{p}\right)\left(\frac{p}{q}+\frac{q}{p}+\frac{p}{q}-\frac{q}{p}\right)-2=\\ \\ \\ =\frac{2q}{p}\cdot \frac{2p}{q}-2=4-2=2$

Ответ: 2.