[2cos40度+cos80度(1+3^1/2tan10度)](1+sin70度)^1/2
=〔2cos40°+ cos80°+√3sin210°/cos10°〕(sin35°+cos35°)
=〔cos40°+2cos60°cos20°+√3(sin10°)^2/cos10°〕(sin35°+cos35°)
=〔cos40°+cos20°+√3(sin10°)^2/cos10°〕(sin35°+cos35°)
=〔2cos30°cos10°+√3(sin10°)^2/cos10°〕(sin35°+cos35°)
=〔√3cos10°+√3(sin10°)^2/cos10°〕(sin35°+cos35°)
=√3/cos10°(sin35°+sin55°)
=√3/cos10°*2sin45°cos10°
=√6