1.Biến đổi thành tích các biểu thức sau A = 1 + 2sin a - cos 2a; B = sin a + sin 2a + sin 3a + si sin4a+sin5a+sin6a C = cos^2 (3a) + cos^2 (2a) - sin^2 a; D = cos^4 a - cos 2a + 2sin^6 a

You are cycling around europe with friends. you book into a hostel and you ask the owner what the ratio of men to women is currently staying there. there are 24 men and 6 women. what is the ratio of men to women in its simplest form?

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?

Acompany wants to reduce the dimensions of its logo by one fourth to use on business cards. if the area of the original logo is 4 square inches, what is the area of the logo that will be used on the business cards?