cosa+sina=0.2,0
cosa+sina=0.2,0
已知sina+cosa=-0.2 (0
sina cosa+sina-cosa=0 求sin2a的值
设tanA= Sina-cosa / Sina+cosa且0
sinA+cosA=tanA(0
已知4sinacosa-5sina-5cosa-1=0求sina.sina.sina+cosa.cosa.cosa的值.
若|cosa|/cosa+sina/|sina|=0,试判断sin(cosa)·cos(sina)的符号
( sina*sina-cosa*cosa)/cos2a*sina+cos2a*cosa)=
求证:1+sina+cosa/1+sina-cosa+1-cosa+sina/1+cosa+sina=2/sina
已知sina-cosa=7/13,a属于(0,180),求sina乘cosa,sina+cosa,tana
(tana-3)(sina+cosa+3=0) 那么4sina-2cosa/5cosa+3sina 的值是多少
(sina绝对值)/sina+(cosa/cosa绝对值)=0,试判断cot(sina)*tan(cosa)的符号.