设，则（为常数）的值．https://img-ph-mirror.nosdn.127.net/OCKSU6xXGRmrhqyAjxCsLQ==/6608185829214053227.pnghttps://img-ph-mirror.nosdn.127.net/JkqlqFql5XkrAZfdvWFndg==/6608888417143176694.pnghttps://img-ph-mirror.nosdn.127.net/twXY8ldkHYPX6F401pfEHA==/6597409515751723222.png