Вычислите (cos105cos5+sin105sin5)/(cos18cos62-sin62cos72)

Вычислите (cos105°cos5°-sin105°sin5°) /(cos18°cos62°-sin62°cos72°). (cos105°cos5°-sin105°sin5°) /(cos18°cos62°-sin62°cos72°) =cos(105°-5°)/(cos(90° -72°)cos62°-sin62°cos72°) =cos100°/(sin72°cos62°-sin62°cos72°)= cos100°/sin(72°-62°) =cos(90°+10°)/sin10°  =-sin10°/sin10°  = -1.