1/sin10-√3/cos10
=(cos10-√3sin10)/sin10cos10
=2(1/2*cos10-√3/2*sin10)/sin10cos10
=2(sin30cos10-cos30sin10)/sin10cos10
=4sin(30-10)/2sin10cos10
=4sin20/sin20
=4
1/sin10-√3/cos10
=(cos10-√3sin10)/sin10cos10
=2(1/2*cos10-√3/2*sin10)/sin10cos10
=2(sin30cos10-cos30sin10)/sin10cos10
=4sin(30-10)/2sin10cos10
=4sin20/sin20
=4