Question

Вычислите
$frac{cos4^{circ}-cos6^{circ}-cos8^{circ}+cos10^{circ}}{sin^{2}1^{circ}cos1^{circ}cos7^{circ} }$

Answer 1

$frac{cos4^{circ }-cos6^{circ }-cos8^{circ }+cos10^{circ }}{sin^21^{circ }cos1^{circ }cos7^{circ }} = -8$

Answer 2

можешь объяснить?