tan75度。tan75=tan(45+30)=(tan45+tan30)/(tan45-tan30)=(1-根号3/3)/(1+根号3/3)=2+根号3。公式：cos(α+β)=cosα·cosβ-sinα·sinβ cos(α-β)=cosα·cosβ+sinα·sinβ sin(α±β)=sinα·cosβ±cosα·sinβ tan(α+β)=(tanα+tanβ)/(1-tanα·tanβ...
∴AB=5/3
(sinα)^2 + (cosα)^2 = 1 α是第二象限，所以cosα < 0 tanα = sinα/cosα ...
(1+根号3倍tan10度)乘cos40度等于多少………要过程…… 解答: =2(sin30°+cos30°tna10°)cos40° =2(sin30°+cos30°sin10°/cos10°)cos40° =2sin(30°+10°)cos40°/cos10° =2sin40°cos40°/ cos10° =sin80°/cos10° =cos10°/cos10° =1 猜你喜欢: 1.当太阳直射在赤道和北...
负2分之一的负1次方加3减派的0次方加3倍的tan60度减根号12 =-2+1+3×√3-2√3 =-1+√3