1/sin10+√3/cos10
=(cos10+√3sin10)/sin10cos10
=2(1/2*cos10+√3/2*sin10)/sin10cos10
=2(sin30cos10+cos30sin10)/sin10cos10
=4sin(30+10)/2sin10cos10
=4sin40/sin20
=8sin20cos20/sin20
=8cos20
你没写错吗?中间是不是-号?