命题“若 则方程有实数根”的逆命题是
sin2(π+α)-cos(π+α)·cos(-α)+1=________.
cos=________.
α是第二象限角,tanα=-,则sinα=________.
设集合M=,N={α|-π<α<π},则M∩N=________.
若角α的终边与直线y=3x重合且sinα<0,又P(m,n)是角α终边上一点,且|OP|=,则m-n=________.