tanx=2,求2/3SIN^2X+1/4cox^2X的值
问题描述：
tanx=2,求2/3SIN^2X+1/4cox^2X的值
答
2/3sin²x+1/4cos²x
=2/3(sin²x+cos²x)/sin²x+1/4*(sin²x+cos²x)/cos²x
=2/3(1+1/4)+1/4*(4+1)
=5/6+5/4
=25/12