Помогите подробно решить тригонометрию

3/8 - 6•sin^2 π/12•cos^2 π/12 = 3/8 - 3/2 • 4•sin^2 π/12•cos^2 π/12 = 3/8 - 3/2 • (2•sin π/12•cos π/12)^2 = 3/8 - 3/2 • sin^2 π/6 = 3/8 - 3/2 • (1/2)^2 = 3/8 - 3/2 • 1/4 =3/8 - 3/8 = 0