1/sin10°-根号3/sin80°
原式=1/sin10-√3/cos10
=(cos10-√3sin10)/sin10cos10
=2(1/2cos10-√3/2*sin10)/sin10cos10
=2cos(10+60)/sin10cos10
=4cos70/sin20
=4请将=2(1/2cos10-√3/2*sin10)/sin10cos10
=2cos(10+60)/sin10cos10
写的更细些不明白2cos(10+60哪来的