化简三角函数
化简(sina+cosa-1)(sina-cosa+1)/sian2a
(sina+cosa-1)(sina-cosa+1)/sin(2a) =[sin^a-(cosa-1)^]/sin(2a) =[(1-cos^a)-(1-cosa)^]/sin(2a) =(1-cosa)[(1+cosa)-(1-cosa)]/sin(2a) =(1-cosa)*2cosa/[2sinacosa] =(1-cosa)/sina =tan(a/2)
答:(sina+cosa-1)(sina-cosa+1) =[sina+(cosa-1)]*[sina-(cosa-1)] =(sina)^2-(cosa-1)^2...详情>>
问:小华5/1小时行了3/2千米他行1千米需要多少小时,他行1小时可行多少千米?(为...
答:1/5÷2/3=1/5×3/2=3/10小时详情>>
问:甲车每小时行38km乙车每小时行41km甲乙车同时两地开岀相向行了2.5小时后相...
答:(38+41)x2.5=197.5千米详情>>