为什么空间直角坐标系中，求某平面的一个法向量不能取（0，0，0），零向量不是与所有平面都垂直吗？ 怎样求平面的法向量。
\u5728\u7a7a\u95f4\u76f4\u89d2\u5750\u6807\u7cfb\u4e2d\uff0c\u5982\u4f55\u6c42\u4e00\u4e2a\u5411\u91cf\u7684\u6cd5\u5411\u91cf\uff1f\u5982\u4f55\u6c42\u4e00\u4e2a\u5e73\u9762\u7684\u6cd5\u5411\u91cf\uff1f\u6ca1\u6709\u5b9a\u4e49\u4e00\u4e2a\u5411\u91cf\u7684\u6cd5\u5411\u91cf
\u53ea\u6709\u4e24\u4e2a\u5411\u91cf\u7684\u5782\u76f4\u5b9a\u4e49
\u4e24\u4e2a\u5411\u91cf\u5782\u76f4,\u5219\u5b83\u4eec\u5bf9\u5e94\u5206\u91cf\u7684\u4e58\u79ef\u4e4b\u548c\u7b49\u4e8e0
\u5982 (x1,x2,x3) \u4e0e (2,-6,-10) \u5782\u76f4 2x1-6x2-10x3 = 0
\u5e73\u9762\u7684\u6cd5\u5411\u91cf\u5373\u4e0e\u4e24\u4e2a\u5df2\u77e5\u5411\u91cf\u90fd\u5782\u76f4\u7684\u5411\u91cf, \u6709\u65e0\u7a77\u591a, \u89e3\u65b9\u7a0b\u5373\u5f97
\u5728\u5e73\u9762\u5185\u627e\u4e24\u4e2a\u4e0d\u5171\u7ebf\u7684\u5411\u91cf\uff0c\u5f85\u6c42\u7684\u6cd5\u5411\u91cf\u4e0e\u8fd9\u4e24\u4e2a\u5411\u91cf\u5404\u505a\u6570\u91cf\u79ef\u4e3a\u96f6\u5c31\u53ef\u4ee5\u786e\u5b9a\u51fa\u6cd5\u5411\u91cf\u4e86\uff0c\u4e3a\u65b9\u4fbf\u8fd0\u7b97\uff0c\u63d0\u53d6\u516c\u56e0\u6570\uff0c\u82e5\u5176\u4e2d\u542b\u6709\u672a\u77e5\u91cfx\uff0c\u4e3ax\u4ee3\u503c\u5373\u53ef\u5f97\u5230\u4e00\u4e2a\u6700\u7b80\u5355\u7684\u6cd5\u5411\u91cf\u3002
\u5982\u5df2\u77e5\u5411\u91cfa\u548cb\u4e3a\u5e73\u9762\u0251\u5185\u4e0d\u5171\u7ebf\u7684\u4e24\u4e2a\u975e\u96f6\u5411\u91cf\uff0c\u4e14a=(x1\uff0cy1\uff0cz1)\uff0cb=(x2\uff0cy2\uff0cz2)\uff0c\u8bben\u4e3a\u5e73\u9762\u0251\u7684\u4e00\u4e2a\u6cd5\u5411\u91cf\uff0cn=(x\uff0cy\uff0cz)\uff0c\u6839\u636e\u65b9\u7a0b\u7ec4\uff0c\u53ef\u5f97\u5230\u6cd5\u5411\u91cfn\u4e2dx\uff0cy\uff0cz\u7684\u5173\u7cfb\u5f0f\uff0c\u4ece\u800c\u6c42\u51fa\u5e73\u9762\u0251\u7684\u4e00\u4e2a\u6cd5\u5411\u91cf\u3002
\u6269\u5c55\u8d44\u6599\uff1a
\u6570\u5b66\u7b54\u9898\u6ce8\u610f\u4e8b\u9879\uff1a
1\u3001\u5de7\u89e3\u9009\u62e9\uff0c\u586b\u7a7a\u9898\uff0c\u89e3\u9009\u62e9\uff0c\u586b\u7a7a\u9898\u7684\u57fa\u672c\u539f\u5219\u662f\u5c0f\u9898\u4e0d\u53ef\u5927\u505a\u3002
2\u3001\u76f4\u63a5\u4ece\u9898\u5e72\u51fa\u53d1\u8003\u8651\uff0c\u63a2\u6c42\u7ed3\u679c\uff0c\u4ece\u9898\u5e72\u548c\u9009\u62e9\u8054\u5408\u8003\u8651\uff0c\u4ece\u9009\u62e9\u51fa\u53d1\u63a2\u6c42\u6ee1\u8db3\u9898\u5e72\u7684\u6761\u4ef6\u3002
3\u3001\u89c4\u8303\u7b54\u9898\u5f88\u91cd\u8981\uff0c\u627e\u5230\u89e3\u9898\u65b9\u6cd5\u540e\u4e66\u5199\u8981\u7b80\u660e\u627c\u8981\uff0c\u5feb\u901f\u89c4\u8303\uff0c\u4e0d\u62d6\u6ce5\u5e26\u6c34\uff0c\u9ad8\u8003\u8bc4\u5206\u662f\u6309\u6b65\u7ed9\u5206\uff0c\u5173\u952e\u6b65\u9aa4\u4e0d\u80fd\u4e22\uff0c\u4f46\u5141\u8bb8\u5408\u7406\u7701\u7565\u975e\u5173\u952e\u6b65\u9aa4\u3002
4\u3001\u7b54\u9898\u65f6\u5c3d\u91cf\u4f7f\u7528\u6570\u5b66\u7b26\u53f7\uff0c\u8fd9\u6bd4\u6587\u5b57\u53d9\u8ff0\u8981\u8282\u7701\u65f6\u95f4\u4e14\u4e25\u8c28\u3002\u5373\u4f7f\u8fc7\u7a0b\u6bd4\u8f83\u7b80\u5355\uff0c\u4e5f\u8981\u7b80\u8981\u5730\u5199\u51fa\u57fa\u672c\u6b65\u9aa4\uff0c\u5426\u5219\u4f1a\u88ab\u6263\u5206\u3002
\u53c2\u8003\u8d44\u6599\u6765\u6e90\uff1a\u767e\u5ea6\u767e\u79d1-\u5e73\u9762\u7684\u6cd5\u5411\u91cf
\u53c2\u8003\u8d44\u6599\u6765\u6e90\uff1a\u767e\u5ea6\u767e\u79d1-\u6cd5\u5411\u91cf
不好说啊，零向量也可以说与所有向量平行啊
法向量的模必须为1
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