化简：根号(1-2sin100°cos280°)/{cos370°-根号[1-cos^2(170°)]}_数学解答

化简：根号(1-2sin100°cos280°)/{cos370°-根号[1-cos^2(170°)]}

人气：410 ℃　时间：2020-04-07 05:13:46

解答

sinαcosβ = [sin(α+β)+sin(α-β)]/2所以sin100cos280 = [sin(α+)+sin(α-β)]/2=sin20/2根号(1-2sin100°cos280°)=根号(1-sin20)=根号(1-2sin10cos10)=cos10-sin10根号[1-cos^2(170°)]=sin(170°)=cos(80°)...