(sin20*sin40*sin110)/(sin60sin30+sin20sin40*cos110)

   1. Преобразуем:

• A = (sin20 * sin40 * sin110)/(sin60 * sin30 + sin20 * sin40 * cos110);
• A = (sin20 * sin40 * sin(90 + 20))/(sin60 * sin30 + sin20 * sin40 * cos(90 + 20));
• A = (sin20 * sin40 * cos20)/(sin60 * sin30 - sin20 * sin40 * sin20);
• A = (sin40 * sin40)/(2sin60 * sin30 - 2sin20 * sin40 * sin20).

   2. Разность косинусов:

• A = sin^2(40)/(sin60 + sin20(cos60 - cos20));
• A = sin^2(40)/(sin60 + sin20(1/2 - cos20));
• A = sin^2(40)/(cos30 + 1/2(sin20 - 2sin20 * cos20);
• A = 2sin^2(40)/(cos30 + 1/2(sin20 - sin40)).

   3. Разность синусов:

• A = 2sin^2(40)/(cos30 - sin10 * cos30);
• A = sin^2(40)/cos30(1 - cos80);
• A = sin^2(40)/cos30 * 2sin^2(40);
• A = 1/2cos30 = 1/(2 * 3/2) = 3/3.

   Ответ: 3/3.