17£®Ä³ÊéµêÏúÊÛ¸Õ¸ÕÉÏÊеÄij֪ÃûÆ·ÅÆµÄ¸ßÈýÊýѧµ¥Ôª¾í£¬°´ÊÂÏÈÄⶨµÄ¼Û¸ñ½øÐÐ5ÌìÊÔÏú£¬Ã¿ÖÖµ¥¼ÛÊÔÏú1Ì죬µÃµ½Èç±íÊý¾Ý£º
µ¥¼Ûx£¨Ôª£©1819202122
ÏúÁ¿y£¨²á£©6156504845
£¨1£©ÇóÊÔÏú5ÌìµÄÏúÁ¿µÄ·½²îºÍy¶ÔxµÄ»Ø¹éÖ±Ïß·½³Ì£»
£¨2£©Ô¤¼Æ½ñºóµÄÏúÊÛÖУ¬ÏúÁ¿Óëµ¥¼Û·þ´Ó£¨1£©ÖеĻع鷽³Ì£¬ÒÑ֪ÿ²áµ¥Ôª¾íµÄ³É±¾ÊÇ14Ôª£¬
ΪÁË»ñµÃ×î´óÀûÈ󣬸õ¥Ôª¾íµÄµ¥¼ÛÓ¦¶¨Îª¶àÉÙÔª£¿
¸½£ºb=$\frac{{\sum_{i=1}^n{{x_i}{y_i}-n\overline x\overline y}}}{{\sum_{i=1}^n{x_i^2}-n{{£¨\overline x£©}^2}}}=\frac{{\sum_{i=1}^n{£¨{x_i}-\overline x£©£¨{y_i}-\overline y}£©}}{{\sum_{i=1}^n{{{£¨{x_i}-\overline x£©}^2}}}}$£¬a=$\overline y$-b$\overline x$£®

·ÖÎö 1£©¼ÆËãÆ½¾ùÊý£¬ÀûÓù«Ê½Çó³öa£¬b£¬¼´¿ÉµÃ³öy¶ÔxµÄ»Ø¹éÖ±Ïß·½³Ì£»
£¨2£©Éè»ñµÃµÄÀûÈóΪzÔª£¬ÀûÓÃÀûÈó=ÏúÊÛÊÕÈë-³É±¾£¬½¨Á¢º¯Êý£¬ÀûÓÃÅä·½·¨¿ÉÇó»ñµÃµÄÀûÈó×î´ó£®

½â´ð ½â£º£¨1£©¡ß$x=\frac{18+19+20+21+22}{5}=20£¬y=\frac{61+56+50+48+45}{5}=52$£¬
$s_y^2=\frac{1}{5}£¨{{9^2}+{4^2}+{2^2}+{4^2}+{7^2}}£©=33.2$£¬
¡ß$\sum_{i=1}^5{£¨{{x_i}-x}£©}£¨{{y_i}-y}£©=-40£¬{\sum_{i=1}^5{£¨{{x_i}-x}£©}^2}=10$£¬
¡à$b=\frac{{\sum_{i=1}^5{£¨{{x_i}-x}£©}£¨{{y_i}-y}£©}}{{{{\sum_{i=1}^5{£¨{{x_i}-x}£©}}^2}}}=-4£¬\widehata=y-\widehatbx=52+20¡Á4=132$£¬
ËùÒÔy¶ÔxµÄ»Ø¹éÖ±Ïß·½³ÌΪ£º$\widehaty=-4\widehatx+132$£®
£¨2£©»ñµÃµÄÀûÈóz=£¨x-14£©y=-4x2+188x-1848£¬
¡ß¶þ´Îº¯Êýz=-4x2+188x-1848µÄ¿ª¿Ú³¯Ï£¬
¡àµ±$x=\frac{188}{8}=23.5$ʱ£¬zÈ¡×î´óÖµ£¬
¡àµ±µ¥¼ÛÓ¦¶¨Îª23.5Ԫʱ£¬¿É»ñµÃ×î´óÀûÈó£®

µãÆÀ ±¾ÌâÖ÷Òª¿¼²é»Ø¹é·ÖÎö£¬¿¼²é¶þ´Îº¯Êý£¬¿¼²éÔËËãÄÜÁ¦¡¢Ó¦ÓÃÒâʶ£¬ÊôÓÚÖеµÌ⣮

Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

7£®Ö±ÈýÀâÖùABC-A1B1C1ÖУ¬¡ÏABC=90¡ã£¬AB=BC=BB1£¬MΪA1B1µÄÖе㣬NÊÇAC1ÓëA1CµÄ½»µã£®
£¨¢ñ£©ÇóÖ¤£ºMN¡ÎÆ½ÃæBCC1B1£»
£¨¢ò£©ÇóÖ¤£ºMN¡ÍÆ½ÃæABC1£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÌî¿ÕÌâ

8£®ÒÑÖªf£¨x£©=£¨a2-2a-2£©xÊÇÔöº¯Êý£¬ÔòʵÊýaµÄȡֵ·¶Î§ÊÇ£¨-¡Þ£¬-1£©¡È£¨3£¬+¡Þ£©£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

5£®»¯¼ò£º
£¨1£©£¨$\frac{2}{3}$£©-2+£¨1-$\sqrt{2}$£©0-£¨3$\frac{3}{8}$£©${\;}^{\frac{2}{3}}$+$\sqrt{£¨3-¦Ð£©^{2}}$£»
£¨2£©$\frac{5}{6}$a${\;}^{\frac{1}{3}}$b-2•£¨-3a${\;}^{-\frac{1}{2}}$b-1£©¡Â£¨4a${\;}^{\frac{2}{3}}$b-3£©${\;}^{\frac{1}{2}}$£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

12£®5ÕÅ¿¨Æ¬ÉÏ·Ö±ðдÓÐÊý×Ö1£¬2£¬3£¬4£¬5£¬´ÓÕâ5ÕÅ¿¨Æ¬ÖÐËæ»ú³éÈ¡2ÕÅ£¬ÔòÈ¡³ö2ÕÅ¿¨Æ¬ÉÏÊý×ÖÖ®ºÍΪżÊýµÄ¸ÅÂÊΪ£¨¡¡¡¡£©
A£®$\frac{3}{5}$B£®$\frac{2}{5}$C£®$\frac{3}{4}$D£®$\frac{2}{3}$

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

2£®ÈçͼËùʾ£¬ÒÑÖªÔ²ÄÚ½ÓËıßÐÎABCD£¬¼ÇT=tan$\frac{A}{2}$+tan$\frac{B}{2}$+tan$\frac{C}{2}$+tan$\frac{D}{2}$£®
£¨1£©ÇóÖ¤£ºT=$\frac{2}{sinA}$+$\frac{2}{sinB}$£»
£¨2£©ÈôAB=6£¬BC=3£¬CD=4£¬AD=5£¬ÇóTµÄÖµ¼°ËıßÐÎABCDµÄÃæ»ýS£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

9£®ÒÑÖªº¯Êýf£¨x£©=ax-$\frac{1}{x^2}$£¬ÇÒf£¨-$\frac{1}{3}$£©=4f£¨$\frac{1}{2}$£©£®
£¨1£©Óö¨Òå·¨Ö¤Ã÷£ºº¯Êýf£¨x£©ÔÚÇø¼ä£¨0£¬+¡Þ£©Éϵ¥µ÷µÝÔö£»
£¨2£©Èô´æÔÚx¡Ê[1£¬3]£¬Ê¹µÃf£¨x£©£¼|x-2|+m£¬ÇóʵÊýmµÄȡֵ·¶Î§£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

6£®ÔÚ¡÷ABCÖУ¬b=asinB£¬Ôò¡÷ABCÒ»¶¨ÊÇ£¨¡¡¡¡£©
A£®¶Û½ÇÈý½ÇÐÎB£®Èñ½ÇÈý½ÇÐÎC£®Ö±½ÇÈý½ÇÐÎD£®µÈÑüÈý½ÇÐÎ

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

7£®É躯Êýf£¨x£©=x2+bln£¨x+1£©£¬ÆäÖÐb¡Ù0£®
£¨¢ñ£©µ±b£¾$\frac{1}{2}$ʱ£¬ÅжϺ¯Êýf£¨x£©ÔÚ¶¨ÒåÓòÉϵĵ¥µ÷ÐÔ£»
£¨¢ò£©µ±b¡Ü$\frac{1}{2}$ʱ£¬Çóº¯Êýf£¨x£©µÄ¼«Öµµã£®

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸