| ²é¿´: 428 | »Ø¸´: 2 | |||
[ÇóÖú]
Ò»µÀ¸ßÖÐÊýѧÌâÇó½â
|
|
ÔÚÈý½ÇÐÎABCÖУ¬A¡¢B¡¢CËù¶ÔµÄ±ß·Ö±ðÊÇa¡¢b¡¢c.ÇÒÂú×ãasinA-csinC=£¨a-b£©sinB Çó½ÇAµÄ´óС£¬ÒÔ¼°cosA+cosBµÄȡֵ·¶Î§ |
» ²ÂÄãϲ»¶
Ò»Ö¾Ô¸ÎäÀí²ÄÁϹ¤³Ì348Çóµ÷¼Á
ÒѾÓÐ7È˻ظ´
306Çóµ÷¼Á
ÒѾÓÐ6È˻ظ´
Ò»Ö¾Ô¸ÉϺ£½»´óÉúÎïÓëҽҩר˶324·Ö£¬Çóµ÷¼Á
ÒѾÓÐ3È˻ظ´
Çóµ÷¼ÁÒ»Ö¾Ô¸º£´ó£¬0703»¯Ñ§Ñ§Ë¶304·Ö£¬Óдó´´ÏîÄ¿£¬Ëļ¶Òѹý
ÒѾÓÐ9È˻ظ´
289²ÄÁÏÓ뻯¹¤£¨085600£©BÇøÇóµ÷¼Á
ÒѾÓÐ4È˻ظ´
08¹¤¿Æ 320×Ü·Ö Çóµ÷¼Á
ÒѾÓÐ11È˻ظ´
Ò»Ö¾Ô¸»ªÖÐũҵ071010£¬×Ü·Ö320Çóµ÷¼Á
ÒѾÓÐ6È˻ظ´
323Çóµ÷¼Á
ÒѾÓÐ5È˻ظ´
284Çóµ÷¼Á
ÒѾÓÐ5È˻ظ´
317Çóµ÷¼Á
ÒѾÓÐ16È˻ظ´
Pchief
Ìú¸Ëľ³æ (ÕýʽдÊÖ)
- ÊýѧEPI: 26
- Ó¦Öú: 13 (СѧÉú)
- ¹ó±ö: 0.024
- ½ð±Ò: 10816.4
- ºì»¨: 36
- Ìû×Ó: 987
- ÔÚÏß: 1992.8Сʱ
- ³æºÅ: 52235
- ×¢²á: 2004-09-04
- רҵ: ·ºº¯·ÖÎö
¡¾´ð°¸¡¿Ó¦Öú»ØÌû
¡ï
math105(½ð±Ò+1): »¶Ó²ÎÓëÌÖÂÛ 2011-04-23 18:55:00
susana33(½ð±Ò+2): 2011-05-14 11:21:19
math105(½ð±Ò+1): »¶Ó²ÎÓëÌÖÂÛ 2011-04-23 18:55:00
susana33(½ð±Ò+2): 2011-05-14 11:21:19
|
Á½±ßÓÃÍâ½ÓÔ²Ö±¾¶³ËµÃ a^2 - c^2 = ab - b^2£¬Òò´Ë cos C = (a^2+b^2 - c^2) / (2ab) = 1/2 ====> C = 60¶È£¬ A+B=120¶È ====> cos A + cos B = cos( (A-B)/2 ) = cos (A- 60¶È) ÒòΪ 0 < A < 120 ¶È ËùÒÔ cos 60¶È < cos A + cos B <= cos 0 ====> 1/2 < cosA + cosB <= 1 |
2Â¥2011-04-23 16:08:54
Rallon
½ð³æ (СÓÐÃûÆø)
- Ó¦Öú: 2 (Ó×¶ùÔ°)
- ½ð±Ò: 1006.1
- Ìû×Ó: 195
- ÔÚÏß: 63Сʱ
- ³æºÅ: 958121
- ×¢²á: 2010-02-28
- ÐÔ±ð: GG
- רҵ: ½ðÊô²ÄÁϵĺϽðÏà¡¢Ïà±ä¼°
¡ï
math105(½ð±Ò+1): »¶Ó²ÎÓëÌÖÂÛ 2011-04-23 18:55:06
math105(½ð±Ò+1): »¶Ó²ÎÓëÌÖÂÛ 2011-04-23 18:55:06
| ¸Ð¾õÕâÌâÄ¿ÓÐÎÊÌ⣬Ӧ¸ÃÊÇÇóCµÄ½Ç¶È£¬ÔÙÇóºóÃæµÄȡֵ·¶Î§£¬CΪ60¶È£¬È¡Öµ·¶Î§,0.5~1,0.5²»°üÀ¨µÈºÅ¡££¬1°üÀ¨µÈºÅ |

3Â¥2011-04-23 16:38:10













»Ø¸´´ËÂ¥