设数列的通项公式为,数列定义如下:对任意,是数列中不大于的项的个数,则__________;数列的前项和__________
若P(-4,3)是角α终边上一点,则的值为________.
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)=________.