计算4/3[cos^2(13π/6)]+3tan^2(π/6)-1/3[sin^2(2π/3)],
问题描述：
计算4/3[cos^2(13π/6)]+3tan^2(π/6)-1/3[sin^2(2π/3)],
答
4/3[cos^2(13π/6)]+3tan^2(π/6)-1/3[sin^2(2π/3)],
=4/3cos^2π/6+3tan^2π/6-1/3sin^2π/3
=4/3*3/4+3*1/9-1/3*3/4
=1+1/3-1/4
=13/12
答
(4/3)*cos²(13π/6)+3tan²(π/6)-(1/3)*sin²(2π/3)=(4/3)*cos²(π/6)+3tan²(π/6)-(1/3)*sin²(π/3)=(4/3)*(√3/2)²+3*(√3/3)²-(1/3)*(√3/2)²=(4/3)*(3/4)+3*(1/3)...