用36米的篱笆靠墙围出一块长方形菜园,菜园面积最大是多少平方米?
\u752836\u7c73\u957f\u7684\u7bf1\u7b06\u56f4\u6210\u4e00\u4e2a\u957f\u65b9\u5f62\u83dc\u56ed\uff0c\u600e\u6837\u56f4\u9762\u79ef\u6700\u5927\u56f4\u6210\u6b63\u65b9\u5f62\uff0c\u8fb9\u957f\u4e3a9
\u6b64\u65f6\u6700\u5927\u9762\u79ef\u662f81
\u8fd9\u662f\u4e2a\u6c42\u6781\u503c\u95ee\u9898\u7684\u9898\u76ee\uff0c\u6839\u636e\u9898\u610f\uff0c\u53ef\u4ee5\u8bbe\u5229\u7528\u7684\u90a3\u6bb5\u56f4\u5899\u7684\u957f\u5ea6\u4e3ax\uff0c\u9762\u79ef\u4e3aS\uff0c\u6545\u53ef\u5f97\u65b9\u7a0b\u5f0f
S = x\uff0836-x\uff09/2\uff0c\u6839\u636e\u629b\u7269\u7ebf\u6c42\u6781\u503c\u95ee\u9898\uff0c\u53ef\u4ee5\u628a\u65b9\u7a0b\u5f0f\u8f6c\u6362\u4e3aS - 162 = -1/2 ( X \u2013 18 )^2\uff0c\u6240\u4ee5\u53ef\u77e5\uff0c\u5f53\u5229\u7528\u56f4\u5899\u7684\u8ddd\u79bb\u4e3a18\u7c73\u65f6\uff0c\u53ef\u4ee5\u5f97\u5230\u6700\u5927\u7684\u9762\u79ef\uff0c\u4e3a162\u5e73\u65b9\u7c73\u3002\u4e5f\u5c31\u662f\u7bf1\u7b06\u7684\u56f4\u6210\u7684\u77e9\u5f62\u7684\u4e09\u4e2a\u5206\u522b\u4e3a9m\uff0c18m\u548c9m\u65f6\uff08\u8fd8\u6709\u4e00\u4e2a\u8fb9\u662f\u56f4\u5899\uff09\uff0c\u5f97\u5230\u7684\u9762\u79ef\u6700\u5927\uff0c\u6700\u5927\u4e3a162\u5e73\u65b9\u7c73\u3002
36÷3=12
12×12=144
绛旓細鎯宠鍥鎴愭渶澶ч潰绉紝灏辫灏介噺鍒╃敤鍥村锛屼互澧欎綔涓闀挎柟褰㈢殑闀匡紝褰撻暱=2X瀹芥椂锛岄潰绉渶澶 瀹=36梅4=9绫 闀=9X2=18绫 闈㈢Н=18X9=162骞虫柟绫
绛旓細鐜嬪彅鍙鐢36绫闀鐨勭绗鍦ㄩ櫌瀛愰噷鍥村嚭涓涓 闀挎柟褰傚寘鎷鏂瑰舰鐨勮姳鍧,鎬庢牱鍥存墠鑳戒娇鑺卞潧鐨勯潰绉渶澶э紵鍥存垚姝f柟褰㈤潰绉渶澶с傛鏂瑰舰杈归暱鏄36梅4=9锛堢背锛夋鏂瑰舰闈㈢Н鏄9脳9=81锛堝钩鏂圭背锛
绛旓細鎴戣涓轰篃鏄162骞虫柟绫筹紝灏辨槸闀垮拰瀹界殑姣斾负2锛1锛屽洜涓鸿鍒╃敤鍒板锛屾墍浠ュ氨涓嶈兘鍐鍥鎴愭鏂瑰舰浜嗐傚叾鏄垜涔熶篃涓嶅お娓呮鍒板簳鏄摢鍧楃煡璇嗘潵瑙e喅锛岃皝鑳芥洿娓呮鐨勮В閲婁竴涓嬪憿锛
绛旓細鍛ㄩ暱鐩稿悓鏃讹紝鍥鎴愮殑闀挎柟褰腑锛屾鏂瑰舰锛堥暱鏂瑰舰鐨勭壒娈婂舰寮忥級闈㈢Н鏈澶с傝竟闀=鍛ㄩ暱梅4 =36梅4 =9绫 姝f柟褰㈤潰绉=9脳9 =81骞虫柟绫
绛旓細鍥鎴愭鏂瑰舰鐨勯潰绉渶澶 36梅3=12锛堢背锛12脳12=144锛堝钩鏂圭背锛
绛旓細闀挎槸瀹界殑2鍊嶆椂,闈㈢Н鏈澶 鍥犳瀹芥槸36梅脳(1+1+2)=9绫,闀挎槸9脳2=18绫虫椂,闈㈢Н鏈澶ф槸162骞虫柟绫
绛旓細鍙互鍥鎴愰暱10绫冲8绫崇殑鑿滃洯鑿滃洯鐨勯潰绉槸闀*娆=10*8=80m2
绛旓細璁鹃暱杈逛负x绫筹紝鍒欏杈逛负锛36-x锛/2锛岄潰绉负(36-x)路x/2 ,x绛変簬18鏃舵渶澶э紝闈㈢Н涓162
绛旓細鍥炵瓟锛36梅2=18
绛旓細36梅锛5+4+4)=36/13 闀=36/13脳5=13,846绫---闀跨殑鍙︿竴杈鐢ㄥ 瀹=36/13脳4=11,077 闈㈢Н=13,846脳11,077=153,57骞虫柟绫 楠岀畢:13,846+11,077+11,077=36