Question

К какому числу равно 1/sin10°-корень из 3/cos10° ¿¿??? (8бал)

Answer 1

1/sin10°- √3/cos10° = (cos10° - √3sin10°)/sin10°cos10° =
= 2((1/2) *cos10° - (√3/2)*sin10°) /(1/2)*2*sin10°cos10°=
= 2(sin30°cos10° - cos30°sin10°) / (1/2)*sin20°=
=2sin(30°-10°) / (1/2)*sin20° = 2*2*sin20°/sin20°=4