Question

10£®ÒÑÖªA£¬BÁ½µØ¹«Â·³¤300km£¬¼×¡¢ÒÒÁ½³µÍ¬Ê±´ÓAµØ³ö·¢ÑØͬһ¹«Â·Ê»ÍùBµØ£¬2Сʱºó£¬¼×³µ½Óµ½µç»°Ðè·µ»ØÕâÌõ¹«Â·ÉϵÄC´¦È¡»Ø»õÎÓÚÊǼ׳µÁ¢¼´Ô­Â··µ»ØC£¬È¡ÁË»õÎïÓÖÁ¢¼´¸ÏÍùBµØ£¨È¡»õÎïµÄʱ¼äºöÂÔ²»¼Æ£©£¬½á¹ûÁ½³µÍ¬Ê±µ½´ïBµØ£®Á½³µµÄËÙ¶ÈʼÖÕ±£³Ö²»±ä£¬ÉèÁ½³µ³ö·¢xСʱºó£¬¼×¡¢ÒÒ¾àÀëAµØµÄ¾àÀë·Ö±ðΪy₁£¨km£©ºÍy₂£¨km£©£¬ËüÃǵĺ¯ÊýͼÏó·Ö±ðÊÇÕÛÏßOPQRºÍÏ߶ÎOR£®
£¨1£©Çó¼×¡¢ÒÒÁ½³µµÄËٶȣ®
£¨2£©ÇóA£¬CÁ½µØÖ®¼äµÄ¾àÀ룮
£¨3£©¼×¡¢ÒÒÁ½³µÔÚ;ÖÐÏàÓöʱ£¬¾àÀëAµØ¶àÔ¶£¿

Answer 1

·ÖÎö £¨1£©¸ù¾ÝËÙ¶È=$\frac{·³Ì}{ʱ¼ä}$£¬·Ö±ð¼ÆËã¼´¿É£»
£¨2£©ÓÉͼÏóºÍÌâÒâ¿ÉµÃ£¬¼×ÐÐÊ»µÄ×ܵÄ·³Ì£¬´Ó¶ø¿ÉÒÔÇóµÃ¼×½Óµ½µç»°·µ»ØC´¦µÄ¾àÀ룬´Ó¶ø¿ÉÒԵõ½A¡¢CÁ½µØÖ®¼äµÄ¾àÀ룻
£¨3£©¸ù¾ÝÌâÒâºÍͼÏ󣬿ÉÒԵõ½PQµÄ½âÎöʽºÍORµÄ½âÎöʽ£¬´Ó¶ø¿ÉÒÔÇóµÃÁ½³µÏàÓöʱµÄʱ¼äºÍ¾àÀëAµØµÄ¾àÀ룮

½â´ð ½â£º£¨1£©ÓÉͼÏó¿ÉÖª£¬¼×³µ2СʱÐÐÊ»µÄ·³ÌÊÇ180km£¬ËùÒԼ׳µËÙ¶ÈÊÇ180¡Â2=90 £¨km/h£©£®
ÒÒ³µ5СʱÐÐÊ»µÄ·³ÌÊÇ300km£¬ËùÒÔÒÒ³µËÙ¶ÈÊÇ300¡Â5=60 £¨km/h£©£®

£¨2£©¼×³µÐÐÊ»µÄ×Ü·³ÌÊÇ90¡Á5=450£¨km£©
¼×´Ó½Óµ½µç»°µ½·µ»ØCµÄ·³ÌÊÇ£¨450-300£©¡Â2=75£¨km£©
ËùÒÔA¡¢CÁ½µØÖ®¼äµÄ¾àÀëÊÇ£º180-75=105£¨km£©
¹ÊA¡¢CÁ½µØÖ®¼äµÄ¾àÀëÊÇ105km£®

£¨3£©ÓÉͼÏóºÍÌâÒâ¿ÉÖª£¬¼×´Ó½Óµ½µç»°·µ»ØC´¦ÓõÄʱ¼äΪ£¨5-$\frac{300}{90}$£©¡Â2=$\frac{5}{6}$Сʱ
¹ÊQµãµÄ×ø±êΪ£¨2$\frac{5}{6}$£¬105£©£¬
Éè¹ýµãP£¨2£¬180£©£¬Q£¨2$\frac{5}{6}$£¬105£©µÄÖ±Ïß½âÎöʽΪy₁=kx+b£¬ÔòÓÐ$\left\{\begin{array}{l}{2k+b=180}\\{2\frac{5}{6}k+b=105}\end{array}\right.$
½âµÃ$\left\{\begin{array}{l}{k=-90}\\{b=360}\end{array}\right.$ËùÒÔÖ±ÏßPQµÄ½âÎöʽΪy₁=-90x+360£¬
Éè¹ýµãO£¨0£¬0£©£¬R£¨5£¬300£©µÄÖ±ÏßOR½âÎöʽΪy₂=mx£¬Ôò300=5m£¬m=60
ÔòÖ±ÏßORµÄ½âÎöʽΪy₂=60x£¨2·Ö£©
ÔòÓÐ$\left\{\begin{array}{l}{y=-90x+360}\\{y=60x}\end{array}\right.$£¬
½âµÃ$\left\{\begin{array}{l}{x=2.4}\\{y=144}\end{array}\right.$£¬
¼´¼×ÒÒÁ½³µÔÚ;ÖÐÏàÓöʱ£¬¾àÀëAµØ144ǧÃ×£®

µãÆÀ ±¾Ì⿼²éÒ»´Îº¯ÊýµÄÓ¦Ó㬽âÌâµÄ¹Ø¼üÊÇÃ÷È·ÌâÒ⣬ÕÒ³öËùÇóÎÊÌâÐèÒªµÄÌõ¼þ£¬ÀûÓÃÊýÐνáºÏµÄ˼Ïë½â´ðÎÊÌ⣮