8£®ÒÑÖªÊýÁÐ{an}Âú×ãan=$\frac{{a}^{n+1}-{a}^{-n-1}}{a-{a}^{-1}}$£¨n¡ÊN*£©£¬a¡Ù-1£¬0£¬1£¬Éèb=a+$\frac{1}{a}$£®
£¨1£©ÇóÖ¤£ºan+1=ban-an-1£¨n¡Ý2£¬n¡ÊN*£©£»
£¨2£©µ±n£¨n¡ÊN*£©ÎªÆæÊýʱ£¬an=$\sum_{i=0}^{\frac{n-1}{2}}£¨-1£©^{i}$C${\;}_{n-1}^{i}$bn-2i£¬²ÂÏëµ±n£¨n¡ÊN*£©ÎªÅ¼Êýʱ£¬an¹ØÓÚbµÄ±í´ïʽ£¬²¢ÓÃÊýѧ¹éÄÉ·¨Ö¤Ã÷£®

·ÖÎö £¨1£©×÷²îÖ¤Ã÷¼´¿É£¬
£¨2£©²ÂÏëanµÄ±í´ïʽ£¬ÀûÓÃÊýѧ¹éÄÉ·¨µÄÖ¤Ã÷²½Öè½øÐÐÖ¤Ã÷£®

½â´ð Ö¤Ã÷£¨1£©ban-an-1=$\frac{£¨a+{a}^{-1}£©£¨{a}^{n+1}-{a}^{-n-1}£©}{a-{a}^{-1}}$-$\frac{{a}^{n}-{a}^{-n}}{a-{a}^{-1}}$=$\frac{{a}^{n+2}-{a}^{-n-2}}{a-{a}^{-1}}$=an+1£¬
£¨2£©²ÂÏën£¨n¡ÊN*£©ÎªÅ¼Êýʱ£¬ÓÐan=$£¨-1£©^{i}{C}_{n-i}^{i}{b}^{n-2i}$£»
ÏÂÃæÍ¬Êýѧ¹éÄÉ·¨Ö¤Ã÷Õâ¸ö²ÂÏ룬
¢Ùµ±n=2ʱ£¬a2=$\frac{{a}^{3}-{a}^{-3}}{a-{a}^{-1}}$=a2+a+a-2=£¨a+$\frac{1}{a}$£©2-1=b2-1£¬½áÂÛ³ÉÁ¢£¬
¢Ú¼ÙÉèµ±n=kʱ£¨kΪżÊý£©Ê±£¬½áÂÛ³ÉÁ¢£¬
¼´ak=£¨-1£©i${C}_{k-i}^{i}$b-2i=bk-${C}_{k-1}^{1}{b}^{k-2}$+¡­+$£¨-1£©^{i}{C}_{k}^{i}{b}^{k-2i}$+¡­+$£¨-1£©^{\frac{k}{2}}$£®´Ëʱk+ÎªÆæÊý£¬
¡àak+1=$£¨-1£©^{i}{C}_{k+1-i}^{i}$bk+1-2i=bk+1-${C}_{k+1}^{1}{b}^{k-1}$+¡­+$£¨-1£©^{i}{C}_{k+1-i}^{i}{b}^{k+1-2i}$+¡­+$£¨-1£©^{\frac{k}{2}}{C}_{\frac{k+2}{2}}^{\frac{k}{2}}b$£¬
µ±n=k+2£¨kΪżÊýʱ£©£¬
ak+2=bak+1-ak=[${b}^{k+2}-{C}_{k}^{1}{b}^{k}+¡­+$$£¨-1£©^{i}{C}_{k+1-i}^{i}{b}^{k+2-2i}$+¡­+$£¨-1£©^{\frac{k}{2}}$${C}_{\frac{k+2}{2}}^{\frac{k}{2}}$b2]-[${b}^{k}-{C}_{k-1}^{1}{b}^{k-2}$+¡­+$£¨-1£©^{i}{C}_{k-i}^{i}{b}^{k-2i}$+¡­+$£¨-1£©^{\frac{k}{2}}$]£¬
=bk+2-bk+¡­+$£¨-1£©^{i}£¨{C}_{k+1-i}^{i}+$${C}_{k-£¨i-1£©}^{i-1}$£©bk+2-2ibk+2-2i+¡­+$£¨-1£©^{\frac{k+2}{2}}$£¬
=bk+2-bk+¡­+$£¨-1£©^{i}{C}_{k+2-i}^{i}$bk+2-2i+¡­+$£¨-1£©^{\frac{k+2}{2}}$£¬
=$£¨-1£©^{i}{C}_{k+2-i}^{i}{b}^{k+2-2i}$£¬½áÂÛÒ²³ÉÁ¢£¬
¸ù¾Ý¢Ù¢Ú£¬¿ÉÖªµ±n£¨n¡ÊN*£©ÎªÅ¼Êýʱ£¬¾ùÓÐan=$£¨-1£©^{i}{C}_{n-i}^{i}{b}^{n-2i}$

µãÆÀ ±¾Ì⿼²éÊýѧ¹éÄÉ·¨£¬¿¼²é²ÂÏëÓëÖ¤Ã÷£¬ÕýÈ·ÔËÓÃÊýѧ¹éÄÉ·¨µÄÖ¤Ã÷²½ÖèÊǹؼü£®

Á·Ï°²áϵÁдð°¸
Ïà¹ØÏ°Ìâ

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º2016-2017ѧÄêÖØÇìÊи߶þÉÏѧÆÚÈëѧ¿¼ÊÔÊýѧÊÔ¾í£¨½âÎö°æ£© ÌâÐÍ£ºÑ¡ÔñÌâ

ijУÏÖÓиßһѧÉú210ÈË£¬¸ß¶þѧÉú270ÈË£¬¸ßÈýѧÉú300ÈË£¬Ó÷ֲã³éÑùµÄ·½·¨´ÓÕâÈý¸öÄê¼¶µÄѧÉúÖÐËæ»ú³éÈ¡nÃûѧÉú½øÐÐÎʾíµ÷²é£¬Èç¹ûÒÑÖª´Ó¸ßһѧÉúÖгéÈ¡µÄÈËÊýΪ7£¬ÄÇô´Ó¸ßÈýѧÉúÖгéÈ¡µÄÈËÊýӦΪ £¨ £©

A.10 B.9 C. 8 D. 7

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

1£®ÒÑÖªÍÖÔ²¦££º$\frac{{x}^{2}}{{a}^{2}}$+$\frac{{y}^{2}}{{b}^{2}}$=1£¨a£¾b£¾0£©£¬¹ýÔ­µãµÄÁ½ÌõÖ±Ïßl1ºÍl2·Ö±ðÓ릣½»ÓÚµãA¡¢BºÍC¡¢D£¬µÃµ½Æ½ÐÐËıßÐÎACBD£®
£¨1£©µ±ACBDΪÕý·½ÐÎʱ£¬Çó¸ÃÕý·½ÐεÄÃæ»ýS£»
£¨2£©ÈôÖ±Ïßl1ºÍl2¹ØÓÚyÖá¶Ô³Æ£¬¦£ÉÏÈÎÒâÒ»µãPµ½l1ºÍl2µÄ¾àÀë·Ö±ðΪd1ºÍd2£¬µ±d12+d22Ϊ¶¨ÖµÊ±£¬Çó´ËʱֱÏßl1ºÍl2µÄбÂʼ°¸Ã¶¨Öµ£®
£¨3£©µ±ACBDΪÁâÐΣ¬ÇÒÔ²x2+y2=1ÄÚÇÐÓÚÁâÐÎACBDʱ£¬Çóa£¬bÂú×ãµÄ¹ØÏµÊ½£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

17£®ÇóÏÂÁм«ÏÞ£º
£¨1£©$\underset{lim}{x¡ú1}$$\sqrt{{x}^{2}+2}$£»
£¨2£©$\underset{lim}{x¡ú\frac{¦Ð}{4}}$£¨sinx-cosx£©£»
£¨3£©$\underset{lim}{x¡ú1}$cos lnx£»
£¨4£©$\underset{lim}{x¡ú0}$esinx£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º2016-2017ѧÄêºÓ±±Ê¡¸ß¶þ8ÔÂÔ¿¼ÊýѧÊÔ¾í£¨½âÎö°æ£© ÌâÐÍ£ºÑ¡ÔñÌâ

ÈôÈý¸öÆ½ÃæÁ½Á½Ïཻ£¬ÓÐÈýÌõ½»Ïߣ¬ÔòÏÂÁÐÃüÌâÖÐÕýÈ·µÄÊÇ£¨ £©

A£®ÈýÌõ½»ÏßΪÒìÃæÖ±Ïß

B£®ÈýÌõ½»ÏßÁ½Á½Æ½ÐÐ

C£®ÈýÌõ½»Ïß½»ÓÚÒ»µã

D£®ÈýÌõ½»ÏßÁ½Á½Æ½Ðлò½»ÓÚÒ»µã

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÌî¿ÕÌâ

13£®ÔÚÊýÁÐ{an}ÖУ¬a1=1£¬a2=2£¬ÆäǰnÏîºÍΪSn£¬ÇÒ{Sn}³ÉµÈ±ÈÊýÁУ¬Ôòa5=54£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

20£®ÓÐÒ»Ãûͬѧ¼Ò¿ªÁËÒ»¸öСÂô²¿£¬ËûΪÁËÑо¿ÆøÎ¶ÔijÖÖÒýÁìÏúÊÛµÄÓ°Ï죬¼Ç¼ÁË2015Äê7ÔÂÖÁ12ÔÂÿÔÂ15ºÅÏÂÎç14ʱµÄÆøÎº͵±ÌìÂô³öµÄÒûÁϱ­Êý£¬µÃµ½ÈçÏÂ×ÊÁÏ£º
ÈÕÆÚ7ÔÂ15ÈÕ8ÔÂ15ÈÕ9ÔÂ15ÈÕ10ÔÂ15ÈÕ11ÔÂ15ÈÕ12ÔÂ15ÈÕ
ÉãÊÏζÈx£¨¡æ£©36353024188
ÒûÁϱ­Êýy27292418155
¸Ãͬѧȷ¶¨µÄÑо¿·½°¸ÊÇ£ºÏÈ´ÓÕâÁù×éÊý¾ÝÖÐѡȡ2×飬ÓÃʣϵÄ4×éÊý¾ÝÇóÏßÐԻع鷽³Ì£¬ÔÙÓñ»Ñ¡ÖеÄ2×éÊý¾Ý½øÐмìÑ飮
£¨1£©Çóѡȡ2×éÊý¾ÝÇ¡ºÃÊÇÏàÁÚµÄÁ½¸öÔµĸÅÂÊ£»
£¨2£©ÈôÑ¡ÖеÄÊÇ8ÔÂÓë12ÔµÄÁ½×éÊý¾Ý£¬¸ù¾ÝʣϵÄ4×éÊý¾Ý£¬Çó³öy¹ØÓÚxµÄÏßÐԻع鷽³Ì$\hat y=bx+\hat a$£®
¸½£º¶ÔÓÚÒ»×éÊý¾Ý£¨x1£¬y1£©£¬£¨x2£¬y2£©£¬¡­£¬£¨xn£¬yn£©£¬Æä»Ø¹éÖ±Ïß$\hat a=\overline y-\hat b\overline x$µÄбÂʺͽؾàµÄ×îС¶þ³Ë¹À¼Æ·Ö±ðΪ£º$b=\frac{{\sum_{i=1}^n{£¨{x_i}-\overline x£©£¨{y_i}-\overline y£©}}}{{\sum_{i=1}^n{{{£¨{x_i}-\overline x£©}^2}}}}=\frac{{\sum_{i=1}^n{{x_i}{y_i}-n\overline x\overline y}}}{{\sum_{i=1}^n{x_i^2-n{{\overline x}^2}}}}$£¬$\hat a=\overline y-\hat b\overline x$£®

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£ºÑ¡ÔñÌâ

15£®É躯Êýf£¨x£©=$\left\{\begin{array}{l}{{2}^{x}-1£¬x¡Ý1}\\{1£¬x£¼1}\end{array}\right.$£¬Ôò²»µÈʽf£¨6-x2£©£¾f£¨x£©µÄ½â¼¯Îª£¨¡¡¡¡£©
A£®£¨-3£¬1£©B£®£¨-2£¬1£©C£®£¨-$\sqrt{5}$£¬2£©D£®£¨-2£¬$\sqrt{5}$£©

²é¿´´ð°¸ºÍ½âÎö>>

¿ÆÄ¿£º¸ßÖÐÊýѧ À´Ô´£º ÌâÐÍ£º½â´ðÌâ

16£®É躯Êýf£¨x£©=£¨x-a£©2lnx£¬a¡ÊR£®
£¨I£©Èôx=eÊÇy=f£¨x£©µÄ¼«Öµµã£¬ÇóʵÊýaµÄÖµ£»
£¨¢ò£©Èôº¯Êýy=f£¨x£©-4e2Ö»ÓÐÒ»¸öÁãµã£¬ÇóʵÊýaµÄȡֵ·¶Î§£®

²é¿´´ð°¸ºÍ½âÎö>>

ͬ²½Á·Ï°²á´ð°¸