ÌâÄ¿ÄÚÈÝ
ij¿ÎÌâѧϰС×éÔÚÒ»´Î»î¶¯ÖжÔÈý½ÇÐεÄÄÚ½ÓÕý·½ÐεÄÓйØÎÊÌâ½øÐÐÁË̽ÌÖ£º¶¨Ò壺Èç¹ûÒ»¸öÕý·½ÐεÄËĸö¶¥µã¶¼ÔÚÒ»¸öÈý½ÇÐεıßÉÏ£¬ÄÇôÎÒÃǾͰÑÕâ¸öÕý·½ÐνÐ×öÈý½ÇÐεÄÄÚ½ÓÕý·½ÐΣ®
½áÂÛ£ºÔÚ̽ÌÖ¹ý³ÌÖУ¬ÓÐÈýλͬѧµÃ³öÈçϽá¹û£º
¼×ͬѧ£ºÔڶ۽ǡ¢Ö±½Ç¡¢²»µÈ±ßÈñ½ÇÈý½ÇÐÎÖзֱð´æÔÚ
ÒÒͬѧ£ºÔÚÖ±½ÇÈý½ÇÐÎÖУ¬Á½¸ö¶¥µã¶¼ÔÚб±ßÉϵÄÄÚ½ÓÕý·½ÐεÄÃæ»ý½Ï´ó£®
±ûͬѧ£ºÔÚ²»µÈ±ßÈñ½ÇÈý½ÇÐÎÖУ¬Á½¸ö¶¥µã¶¼Ôڽϴó±ßÉϵÄÄÚ½ÓÕý·½ÐεÄÃæ»ý·´¶ø½ÏС£®
ÈÎÎñ£º£¨1£©Ìî³ä¼×ͬѧ½áÂÛÖеÄÊý¾Ý£»
£¨2£©ÒÒͬѧµÄ½á¹ûÕýÈ·Âð£¿Èô²»ÕýÈ·£¬Çë¾Ù³öÒ»¸ö·´Àý²¢Í¨¹ý¼ÆËã¸øÓè˵Ã÷£¬ÈôÕýÈ·£¬Çë¸ø³öÖ¤Ã÷£»
£¨3£©ÇëÄã½áºÏ£¨2£©µÄÅж¨£¬ÍƲâ±ûͬѧµÄ½áÂÛÊÇ·ñÕýÈ·£¬²¢Ö¤Ã÷£®
·ÖÎö£º£¨1£©·Ö±ð»Ò»Ï¼´¿ÉµÃ³ö´ð°¸£»
£¨2£©ÏÈÅжϣ¬ÔÙ¾ÙÒ»¸öÀý×Ó£»ÀýÈ磺ÔÚRt¡÷ABCÖУ¬¡ÏB=90¡ã£¬AB=BC=1£¬ÔòAC=
£®
£¨3£©ÏÈÅжϣ¬ÔÙ¾ÙÒ»¸öÀý×Ó£ºÉè¡÷ABCµÄÈýÌõ±ß·Ö±ðΪa£¬b£¬c£¬²»·ÁÉèa£¾b£¾c£¬ÈýÌõ±ßÉϵĶÔÓ¦¸ß·Ö±ðΪha£¬hb£¬hc£¬ÄÚ½ÓÕý·½Ðεı߳¤·Ö±ðΪxa£¬xb£¬xc£®
£¨2£©ÏÈÅжϣ¬ÔÙ¾ÙÒ»¸öÀý×Ó£»ÀýÈ磺ÔÚRt¡÷ABCÖУ¬¡ÏB=90¡ã£¬AB=BC=1£¬ÔòAC=
2 |
£¨3£©ÏÈÅжϣ¬ÔÙ¾ÙÒ»¸öÀý×Ó£ºÉè¡÷ABCµÄÈýÌõ±ß·Ö±ðΪa£¬b£¬c£¬²»·ÁÉèa£¾b£¾c£¬ÈýÌõ±ßÉϵĶÔÓ¦¸ß·Ö±ðΪha£¬hb£¬hc£¬ÄÚ½ÓÕý·½Ðεı߳¤·Ö±ðΪxa£¬xb£¬xc£®
½â´ð£º½â£º£¨1£©1£¬2£¬3£®£¨3·Ö£©
£¨2£©ÒÒͬѧµÄ½á¹û²»ÕýÈ·£®£¨4·Ö£©
ÀýÈ磺ÔÚRt¡÷ABCÖУ¬¡ÏB=90¡ã£¬AB=BC=1£¬ÔòAC=
£®
Èçͼ¢Ù£¬ËıßÐÎDEFBÊÇÖ»ÓÐÒ»¸ö¶¥µãÔÚб±ßÉϵÄÄÚ½ÓÕý·½ÐΣ®
ÉèËüµÄ±ß³¤Îªa£¬ÔòÒÀÌâÒâ¿ÉµÃ£º
=
£¬¡àa=
£¬
Èçͼ¢Ú£¬ËıßÐÎDEFHÁ½¸ö¶¥µã¶¼ÔÚб±ßÉϵÄÄÚ½ÓÕý·½ÐΣ®
ÉèËüµÄ±ß³¤Îªb£¬ÔòÒÀÌâÒâ¿ÉµÃ£º
=
£¬¡àb=
£®
¡àa£¾b£®£¨7·Ö£©
£¨3£©±ûͬѧµÄ½áÂÛÕýÈ·£®
Éè¡÷ABCµÄÈýÌõ±ß·Ö±ðΪa£¬b£¬c£¬²»·ÁÉèa£¾b£¾c£¬ÈýÌõ±ßÉϵĶÔÓ¦¸ß·Ö±ðΪha£¬hb£¬hc£¬ÄÚ½ÓÕý·½Ðεı߳¤·Ö±ðΪxa£¬xb£¬xc£®
ÒÀÌâÒâ¿ÉµÃ£º
=
£¬¡àxa=
£®Í¬Àíxb=
£®
¡ßxa-xb=
-
=
-
=2S£¨
-
£©
=
£¨b+hb-a-ha£©£®
=
£¨b+
-a-
£©£®
=
•£¨b-a£©£¨1-
£©£®
=
•£¨b-a£©£¨1-
£©£®
ÓÖ¡ßb£¼a£¬ha£¼b£¬¡à£¨b-a£©£¨1-
£©£¼0£¬
¡àxa£¼xb£¬¼´xa2£¼xb2£®
¡àÔÚ²»µÈ±ßÈñ½ÇÈý½ÇÐÎÖУ¬Á½¸ö¶¥µã¶¼Ôڽϴó±ßÉϵÄÄÚ½ÓÕý·½ÐεÄÃæ»ý·´¶ø½ÏС£®£¨10·Ö£©
£¨2£©ÒÒͬѧµÄ½á¹û²»ÕýÈ·£®£¨4·Ö£©
ÀýÈ磺ÔÚRt¡÷ABCÖУ¬¡ÏB=90¡ã£¬AB=BC=1£¬ÔòAC=
2 |
Èçͼ¢Ù£¬ËıßÐÎDEFBÊÇÖ»ÓÐÒ»¸ö¶¥µãÔÚб±ßÉϵÄÄÚ½ÓÕý·½ÐΣ®
ÉèËüµÄ±ß³¤Îªa£¬ÔòÒÀÌâÒâ¿ÉµÃ£º
a |
1 |
1-a |
1 |
1 |
2 |
Èçͼ¢Ú£¬ËıßÐÎDEFHÁ½¸ö¶¥µã¶¼ÔÚб±ßÉϵÄÄÚ½ÓÕý·½ÐΣ®
ÉèËüµÄ±ß³¤Îªb£¬ÔòÒÀÌâÒâ¿ÉµÃ£º
b | ||
|
| ||||
|
| ||
3 |
¡àa£¾b£®£¨7·Ö£©
£¨3£©±ûͬѧµÄ½áÂÛÕýÈ·£®
Éè¡÷ABCµÄÈýÌõ±ß·Ö±ðΪa£¬b£¬c£¬²»·ÁÉèa£¾b£¾c£¬ÈýÌõ±ßÉϵĶÔÓ¦¸ß·Ö±ðΪha£¬hb£¬hc£¬ÄÚ½ÓÕý·½Ðεı߳¤·Ö±ðΪxa£¬xb£¬xc£®
ÒÀÌâÒâ¿ÉµÃ£º
xa |
a |
ha-xa |
ha |
aha |
a+ha |
bhb |
b+hb |
¡ßxa-xb=
aha |
a+ha |
bhb |
b+hb |
2S |
a+ha |
2S |
b+hb |
=2S£¨
1 |
a+ha |
1 |
b+ hb |
=
2S |
(a+ha)(b+hb) |
=
2S |
(a+ha)(b+hb) |
2S |
b |
2S |
a |
=
2S |
(a+ha)(b+hb) |
2S |
ab |
=
2S |
(a+ha)(b+hb) |
ha |
b |
ÓÖ¡ßb£¼a£¬ha£¼b£¬¡à£¨b-a£©£¨1-
ha |
b |
¡àxa£¼xb£¬¼´xa2£¼xb2£®
¡àÔÚ²»µÈ±ßÈñ½ÇÈý½ÇÐÎÖУ¬Á½¸ö¶¥µã¶¼Ôڽϴó±ßÉϵÄÄÚ½ÓÕý·½ÐεÄÃæ»ý·´¶ø½ÏС£®£¨10·Ö£©
µãÆÀ£º±¾ÌâÊÇÒ»µÀÄѶȽϴóµÄÌâÄ¿£¬¿¼²éÁËÏàËÆÈý½ÇÐεÄÅж¨ºÍÐÔÖÊÒÔ¼°Õý·½ÐεÄÐÔÖÊ£¬¾Ù³öÀý×ÓÊǽâ´ËÌâµÄ¹Ø¼ü£®
Á·Ï°²áϵÁдð°¸
Ïà¹ØÌâÄ¿