已知| a | =" |" b | =" 2," a·b =" -2," 且(a + b)⊥(a + b), 则实数的值为
是的
设为坐标原点,,若满足,则的最大值为
下列双曲线中,渐近线方程是的是
设全集,集合,则
已知复数的实部和虚部相等,则实数等于