1) 7tg (2π+π-α)*ctgα= 7tg(π-α)*ctgα= - 7tgα*ctgα= -7
2) sinα=√(1-cos²α)=√(1-1/9)=√(8/9)
3√2 * √(8/9)=3*√(16/9)=3*4/3=4
3) 8√3 *cos(π/2 - π/12)*cos(π/12)*sin(π/6)=8√3 * sin (π/12)*cos (π/12)*1/2=
=4√3 * sin (π/6) * 1/2= 2√3 * 1/2 = √3
1) 12sin24*cos24/sin48=6sin48/sin48=6
3) = (sin²(90-47) + cos² (270-47))/2=(sin²47+cos²47)/2=1/2