从等腰直角的底边上任取一点,则为锐角三角形的概率为 .
已知sinα是方程5x2-7x-6=0的根,α是第三象限角,则=________.
化简=________.
sin21°+sin22°+sin23°+…+sin288°+sin289°+sin290°的值为________.
.化简: (1)=________; (2)sin2(-α)-tan(360°-α)tan(-α)-sin(180°-α)cos(360°-α)tan(180°+α)=________; (3)=________.
sin,cos,tan,从小到大的顺序是________.