ÌâÄ¿ÄÚÈÝ

13£®´Ó2¿ªÊ¼£¬Á¬ÐøµÄżÊýÏà¼Ó£¬ËüÃǺ͵ÄÇé¿öÈç±í£º
¼ÓÊýµÄ¸öÊýnÁ¬ Ðø Å¼ Êý µÄ ºÍ S
12=1¡Á2
22+4=6=2¡Á3
32+4+6=12=3¡Á4
42+4+6+8=20=4¡Á5
52+4+6+8+10=30=5¡Á6
¡­¡­
£¨1£©Èç¹ûn=7ʱ£¬ÄÇôSµÄֵΪ56£»
£¨2£©¸ù¾Ý±íÖеĹæÂɲÂÏ룺ÓÃnµÄ´úÊýʽ±íʾSµÄ¹«Ê½Îª S=2+4+6+8+¡­+2n=n£¨n+1£©£»
£¨3£©¸ù¾ÝÉÏÌâµÄ¹æÂɼÆËã32+34+36+¡­+398+400µÄÖµ£¨ÒªÓмÆËã¹ý³Ì£©£®

·ÖÎö £¨1£©¸ù¾Ý±í¸ñÖÐÊý×ֵı仯¹æÂÉ¿ÉÒÔ½â´ð±¾Ì⣻
£¨2£©¸ù¾Ý±í¸ñÖÐÊý×ֵı仯¹æÂÉ¿ÉÒÔ½â´ð±¾Ì⣻
£¨3£©¸ù¾ÝÌâÒ⣬¿ÉÒԵõ½ÌâÄ¿ÖÐʽ×ÓµÈÓÚǰ200¸öÊý¼õȥǰ15¸öÊý£¬±¾ÌâµÃÒÔ½â¾ö£®

½â´ð ½â£º£¨1£©ÓÉÌâÒâ¿ÉµÃ£¬
µ±n=7ʱ£¬S=7¡Á8=56£¬
¹Ê´ð°¸Îª£º56£»
£¨2£©S=2+4+6+8+¡­+2n=n£¨n+1£©£¬
¹Ê´ð°¸Îª£ºn£¨n+1£©£»
£¨3£©32+34+36+¡­+398+400
=£¨2+4+¡­+32+34+36+¡­+398+400£©-£¨2+4+¡­+30£©
=200¡Á201-15¡Á16
=40200-240
=39960£®

µãÆÀ ±¾Ì⿼²é¹æÂÉÐÔ£ºÊý×ֵı仯À࣬½âÌâµÄ¹Ø¼üÊÇÃ÷È·ÌâÒ⣬ÕÒ³öÌâÄ¿ÖÐÊý×ֱ仯µÄ¹æÂÉ£®

Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿

Î¥·¨ºÍ²»Á¼ÐÅÏ¢¾Ù±¨µç»°£º027-86699610 ¾Ù±¨ÓÊÏ䣺58377363@163.com

¾«Ó¢¼Ò½ÌÍø