Question

Какому числу равно:
$\frac{1}{sin10}-\frac{\sqrt{3}}{cos10}$

Answer 1

1/sin10-√3/cos10=(cos10-√3sin10)/sin10cos10=2(1/2cos10-√3/2sin10)=
=2(sin30cos10-cos30sin10)/0,5sin20=4sin(30-10)/sin20=4sin20/sin20=4

Answer 2

$\frac{1}{sin10} - \frac{ \sqrt{3} }{cos10}$ = $\frac{-( \sqrt{3sin \frac{ \pi }{18}-cos \frac{ \pi }{18} } }{cos( \pi :18) sin( \pi :18)}$ =4

Ответ:4