é®é¢ï¼å¦å¾ï¼å¨å¹³é¢ç´è§åæ ç³»xOyä¸ï¼å·²ç¥ç´çº¿l1ï¼y= 12xä¸ç´çº¿l2ï¼y=-x+6ç¸äº¤äºç¹Mï¼ç´çº¿l2ä¸xè½´ç¸äº¤äºç¹Nï¼
ï¼1ï¼æ±Mï¼Nçåæ ï¼
ï¼2ï¼ç©å½¢ABCDä¸ï¼å·²ç¥AB=1ï¼BC=2ï¼è¾¹ABå¨xè½´ä¸ï¼ç©å½¢ABCD沿xè½´èªå·¦åå³ä»¥æ¯ç§1个åä½é¿åº¦çé度移å¨ï¼è®¾ç©å½¢ABCDä¸â³OMNçéå é¨åçé¢ç§¯ä¸ºSï¼ç§»å¨çæ¶é´ä¸ºtï¼ä»ç¹Bä¸ç¹Oéåæ¶å¼å§è®¡æ¶ï¼å°ç¹Aä¸ç¹Néåæ¶è®¡æ¶å¼å§ç»æï¼ï¼ç´æ¥ååºSä¸èªåétä¹é´çå½æ°å
³ç³»å¼ï¼ä¸éè¦ç»åºè§£çè¿ç¨ï¼ï¼
ï¼3ï¼å¨ï¼2ï¼çæ¡ä»¶ä¸ï¼å½t为ä½å¼æ¶ï¼Sçå¼æ大ï¼å¹¶æ±åºæ大å¼ï¼
解ï¼ï¼1ï¼è§£æ¹ç¨ç»y=12xy=-x+6ï¼
解å¾ï¼x=4y=2ï¼
åMçåæ æ¯ï¼ï¼4ï¼2ï¼ï¼
å¨è§£æå¼y=-x+6ä¸ï¼ä»¤y=0ï¼è§£å¾ï¼x=6ï¼åNçåæ æ¯ï¼ï¼6ï¼0ï¼ï¼
ï¼2ï¼å½0â¤tâ¤1æ¶ï¼éåé¨åæ¯ä¸ä¸ªä¸è§å½¢ï¼OB=tï¼åé«æ¯12tï¼åé¢ç§¯æ¯12Ãt�6�112t=14t2ï¼
å½1ï¼tâ¤4æ¶ï¼éåé¨åæ¯ç´è§æ¢¯å½¢ï¼æ¢¯å½¢çé«æ¯1ï¼ä¸åºæ¯ï¼12tï¼ä¸åºæ¯ï¼12ï¼t-1ï¼ï¼æ ¹æ®æ¢¯å½¢çé¢ç§¯å
¬å¼å¯ä»¥å¾å°ï¼S=12[12t+12ï¼t-1ï¼]=12ï¼t-12ï¼ï¼
å½4ï¼tâ¤5æ¶ï¼è¿Mä½xè½´çå线ï¼åéåé¨å被å线åæ两个ç´è§æ¢¯å½¢ï¼ä¸¤ä¸ªæ¢¯å½¢çä¸åºé½æ¯2ï¼ä¸åºåå«æ¯ï¼-t+6å12ï¼t-1ï¼ï¼æ ¹æ®æ¢¯å½¢çé¢ç§¯å
¬å¼å³å¯æ±å¾
S=-34t2+132t-494ï¼
å½5ï¼tâ¤6æ¶ï¼éåé¨åæ¯ç´è§æ¢¯å½¢ï¼ä¸å½1ï¼tâ¤4æ¶ï¼éåé¨åæ¯ç´è§æ¢¯å½¢ç计ç®æ¹æ³ç¸åï¼åS=7-2tï¼
å½6ï¼tâ¤7æ¶ï¼éåé¨åæ¯ç´è§ä¸è§å½¢ï¼åä¸å½0â¤tâ¤1æ¶ï¼è§£æ³ç¸åï¼å¯ä»¥æ±å¾S=12ï¼7-tï¼2ï¼
åï¼S=14t2(0â¤tâ¤1)12(t-12)(1ï¼tâ¤4)-34t2+132t-494(4ï¼tâ¤5)7-2t(5ï¼tâ¤6)12(7-t)2(6ï¼tâ¤7)
ï¼3ï¼å¨0â¤tâ¤1æ¶ï¼å½æ°çæ大å¼æ¯ï¼14ï¼
å½1ï¼tâ¤4ï¼å½æ°å¼yéxçå¢å¤§èå¢å¤§ï¼åå½x=4æ¶ï¼åå¾æ大å¼æ¯ï¼12ï¼4-12ï¼=74ï¼
å½4ï¼tâ¤5æ¶ï¼æ¯äºæ¬¡å½æ°ï¼å¯¹ç§°è½´x=133ï¼åæ大å¼æ¯ï¼-34Ãï¼133ï¼2+132Ã133-494=116ï¼
å½5ï¼tâ¤6æ¶ï¼å½æ°yétçå¢å¤§èåå°ï¼å èå½æ°å¼ä¸å®å°äº116ï¼
åçï¼å½6ï¼tâ¤7æ¶ï¼yétçå¢å¤§èåå°ï¼å èå½æ°å¼å°äº116ï¼
æ»ï¼å½æ°çæ大å¼æ¯ï¼116ï¼
温馨提示:答案为网友推荐,仅供参考