Solve 1+1+2/(1-tan²x )-(3-tan²x)/(1-3 tan²x )=0
Prove that:tan-11/3+tan-11/5+tan-11/7+tan-11/8=45°
Prove that:(sin75°+sin15°)/(sin75°-sin15°)=tan60°
Transform the difference of two squares into a rectangle, the ratio of two sides being 2 : 3.
Evaluate to four significant figure by logarithm,
Simplify yz(x+a)/(x-y)(x-z)+zx(y+a)/(y-z)(y-x)+xy(z+a)/(z-x)(z-y)
如图是函数y=2sin(ωx+φ)(|φ|<π/2)的图像,那么【 】
函数y=sinx/|sinx|+|cosx|/cosx+tanx/|tanx|+|cotx|/cotx的值域是【 】
设函数y=arctanx的图像沿x轴正方向平移两个单位所得到的图像为C.又设C'与C关于原点对称 ,那么C'所对应的图像是【 】
函数y=sinxcosx+sinx+cosx的最大值是______.
在△ABC中,已知cosA=-3/5,则sin(A/2)=______.
设α角属于第Ⅱ象限,且|cos α/2|=-cos α/2,则α/2角属于【 】