是以(1/2)为底x²+kx+2的对数吗?如果是的话,记以a为底b的对数为log【a】b有：因为：log【1/2】(x²+kx+2)∈R所以：x²+kx+2＞0x²+2×(k/2)x+(k/2)²-(k/2)²+2＞0(x+k/2)²＞(k/2)...