如图,以O为圆心,任意长为半径画弧,与射线OM相交于点A,再以点A为圆心,AO长为半径画弧,两弧交于点B,画射线OB,则sin∠AOB的值等于______.
简便计算:=_______;______.
分解因式:=____________;=____________.
计算: =_______;=___________.
比较大小:.
=_________.