1/cos50度+tan10度=?

1/cos50°+tg10°=1/sin40° + sin10°/cos10°
=1/sin40° +(sin10°*2sin10°) /(cos10°*2sin10°)
=1/sin40° +2(sin10°)^2 /sin20°
=1/sin40° +(1-cos20°) /sin20°
=1/sin40°+(1-cos20°)*2cos20° /sin20°*2cos20°
=[1+2cos20°-2(cos20°)^2] /sin40°
=(2cos20°-cos40°) /sin40°
=(cos20°+2sin30°sin10°) /sin40°
=(sin70°+sin10°) /sin40°
=[sin(40°+30°)+sin(40°-30°)] /sin40°
=2sin40°cos30°/sin40°=2cos30°=√3

1/cos50+tan10
=1/sin40+cos80/sin80
=(2cos40+cos80)/sin80
=(2sin(60-10)+sin10)/cos10
=(√3cos10-sin10+sin10)/cos10
=√3