— The summer holiday is on the way. We'll have more freedom.
— . But we should learn to manage ourselves.
A:I'd love to
B:I agree with you
C:I'm afraid I won't
(Ⅰ)以直角坐标系的原点为极点,x轴的正半轴为极轴,并在两种坐标系中取相同的长度单位已知直线的极坐标方程为θ=π4(ρ∈R),它与曲线x=2+5sinθy=1+5sinθ(θ为参数)相交于两点A和B,求|AB|;
(Ⅱ)已知极点与原点重合,极轴与x轴正半轴重合,若直线C1的极坐标方程为:ρcos(θ﹣π4),曲线C2的参数方程为:x=1+cosθy=3+sinθ(θ为参数),试求曲线C2关于直线C1对称的曲线的直角坐标方程.
如图,长为2l的直导线折成边长相等,夹角为60°的V形,并置于与其所在平面相垂直的匀强磁场中,磁感应强度为B.当在该导线中通以电流强度为I的电流时,该V形通电导线受到的安培力大小为( )
已知:如图所示,以梯形ABCD的对角线AC及腰AD为邻边作平行四边形ACED,连接EB,DC的延长线交BE于F.求证:EF=BF.