锟斤拷一锟斤拷(sh锟斤拷)锟絎(xu锟斤拷)锟教帮拷锟斤拷锟斤拷锟饺差數(sh锟斤拷)锟叫碉拷前n锟�(xi锟斤拷ng)锟酵★拷锟节讹拷锟絥锟絩(sh锟斤拷)

锟斤拷锟斤拷锟教學(xu锟斤拷)目锟侥ｏ拷

锟斤拷锟斤拷1.锟組(j锟斤拷n)一锟斤拷锟届練锟斤拷锟秸等差數(sh锟斤拷)锟叫碉拷通锟�(xi锟斤拷ng)锟斤拷式锟斤拷前n锟�(xi锟斤拷ng)锟酵癸拷式.2.锟剿斤拷炔顢�(sh锟斤拷)锟叫碉拷一些锟斤拷锟絴(zh锟斤拷)锟斤拷锟斤拷锟斤拷(hu锟斤拷)锟斤拷锟斤拷锟斤拷锟斤拷Q一些锟斤拷锟絇(gu锟斤拷n)锟斤拷锟絵.

锟斤拷锟斤拷锟教學(xu锟斤拷)锟斤拷锟絚(di锟斤拷n)锟斤拷

锟斤拷锟斤拷锟届練锟斤拷锟秸等差數(sh锟斤拷)锟叫碉拷锟斤拷凸锟绞斤拷虒W(xu锟斤拷)锟統锟絚(di锟斤拷n)锟斤拷锟絗锟筋應(y锟斤拷ng)锟斤拷锟斤拷凸锟绞斤拷锟絈锟斤拷锟絵

锟斤拷锟斤拷锟教學(xu锟斤拷)锟絕锟教ｏ拷

锟斤拷锟斤拷一锟斤拷锟斤拷(f锟斤拷)锟斤拷(x锟斤拷)锟斤拷锟诫：

锟斤拷锟斤拷锟斤拷锟饺回戯拷一锟斤拷锟斤拷一锟斤拷(ji锟斤拷)锟絥锟斤拷锟絎(xu锟斤拷)锟斤拷要锟斤拷(n锟斤拷i)锟捷ｏ拷

锟斤拷锟斤拷1.锟饺差數(sh锟斤拷)锟叫碉拷前锟�(xi锟斤拷ng)锟酵癸拷式1锟斤拷

锟斤拷锟斤拷2.锟饺差數(sh锟斤拷)锟叫碉拷前锟�(xi锟斤拷ng)锟酵癸拷式2锟斤拷

锟斤拷锟斤拷3.锟斤拷锟斤拷(d锟斤拷ng)d≠0锟斤拷锟斤拷一锟斤拷(g锟斤拷)锟斤拷锟斤拷(sh锟斤拷)锟�(xi锟斤拷ng)锟斤拷锟斤拷亩锟斤拷锟绞�

锟斤拷锟斤拷4.锟斤拷(du锟斤拷)锟饺差數(sh锟斤拷)锟斤拷前锟�(xi锟斤拷ng)锟酵碉拷锟斤拷值锟斤拷锟絵锟叫兩種锟斤拷锟斤拷:锟斤拷1锟斤拷锟斤拷锟斤拷:锟斤拷(d锟斤拷ng)>0锟斤拷d<0锟斤拷前n锟�(xi锟斤拷ng)锟斤拷锟斤拷锟斤拷锟街�锟斤拷锟斤拷锟斤拷≥0锟斤拷锟斤拷≤0锟斤拷锟斤拷锟絥锟斤拷值锟斤拷锟斤拷(d锟斤拷ng)<0锟斤拷d>0锟斤拷前n锟�(xi锟斤拷ng)锟斤拷锟斤拷锟斤拷小值锟�锟斤拷锟斤拷锟�≤0锟斤拷锟斤拷≥0锟斤拷锟斤拷锟絥锟斤拷值锟斤拷锟斤拷2锟斤拷锟斤拷锟矫ｏ拷锟缴讹拷锟轿猴拷锟斤拷(sh锟斤拷)锟戒方锟斤拷锟斤拷锟斤拷锟街碉拷r(sh锟斤拷)n锟斤拷值锟斤拷

锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟絵锟絭锟斤拷

锟斤拷锟斤拷锟斤拷1.锟斤拷知锟饺差數(sh锟斤拷)锟叫碉拷前锟�(xi锟斤拷ng)锟酵烇拷锟斤拷前锟�(xi锟斤拷ng)锟酵烇拷锟斤拷锟斤拷前锟�(xi锟斤拷ng)锟酵ｏ拷锟解：锟斤拷锟絵锟絆(sh锟斤拷)∴锟斤拷锟斤拷2锟斤拷知一锟斤拷(g锟斤拷)锟饺差數(sh锟斤拷)锟叫碉拷前锟斤拷锟�(xi锟斤拷ng)锟酵烇拷21锟斤拷锟斤拷锟斤拷锟�(xi锟斤拷ng)锟酵烇拷67锟斤拷前n锟�(xi锟斤拷ng)锟酵烇拷286锟斤拷锟斤拷锟�(xi锟斤拷ng)锟斤拷(sh锟斤拷).

锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟叫窮锟斤拷(sh锟斤拷)锟斤拷{an}锟斤拷前n锟�(xi锟斤拷ng)锟斤拷sn锟斤拷平锟斤拷值锟斤拷锟斤拷锟斤拷(sh锟斤拷)锟叫碉拷平锟斤拷值锟斤拷記锟斤拷锟斤拷锟斤拷锟絫sn=n.锟斤拷锟斤拷(j锟斤拷)锟饺差數(sh锟斤拷)锟叫碉拷锟斤拷锟絴(zh锟斤拷)锟斤拷知锟斤拷.(锟金案ｏ拷n=26).

锟斤拷锟斤拷锟斤拷3锟饺差數(sh锟斤拷)锟斤拷锟叫ｏ拷該锟斤拷(sh锟斤拷)锟叫碉拷前锟斤拷锟斤拷锟�(xi锟斤拷ng)锟斤拷锟斤拷锟�锟�锟斤拷

锟斤拷锟斤拷思路1锟斤拷锟斤拷锟絪n锟侥猴拷锟斤拷(sh锟斤拷)锟斤拷锟斤拷式锟斤拷n锟侥讹拷锟轿猴拷锟斤拷(sh锟斤拷),锟斤拷锟斤拷锟斤拷锟襟函旓拷(sh锟斤拷)取锟斤拷锟斤拷小值锟絩(sh锟斤拷)锟斤拷n值.思路2锟斤拷锟斤拷锟斤拷锟铰烇拷0锟侥等差數(sh锟斤拷)锟叫等差數(sh锟斤拷)锟斤拷前n锟�(xi锟斤拷ng)锟斤拷锟斤拷小锟侥條锟斤拷锟介：思路3锟斤拷锟斤拷s9=s12锟斤拷s12-s9=a10+a11+a12=0锟斤拷a11=0.锟斤拷4.锟斤拷知锟斤拷(sh锟斤拷)锟斤拷{an}锟斤拷前n锟�(xi锟斤拷ng)锟斤拷锟斤拷锟斤拷(sh锟斤拷)锟斤拷{|an|}锟斤拷前n锟�(xi锟斤拷ng)锟斤拷tn.锟解：锟斤拷(d锟斤拷ng)锟絩(sh锟斤拷)锟斤拷锟斤拷n=1也锟絤锟斤拷锟斤拷式锟斤拷∴锟斤拷(sh锟斤拷)锟叫碉拷通锟�(xi锟斤拷ng)锟斤拷式锟斤拷an=-3n+104(锟斤拷锟斤拷an=-3n+104≥0锟斤拷n≤34.7锟斤拷锟斤拷锟斤拷(d锟斤拷ng)n≤34锟絩(sh锟斤拷)锟斤拷an>0,锟斤拷(d锟斤拷ng)n≥35锟絩(sh锟斤拷)an<0.(1)锟斤拷锟斤拷(d锟斤拷ng)n≤34锟絩(sh锟斤拷)锟斤拷tn=|a1|+|a2|+…+|an|=a1+a2+…+an=.(2)锟斤拷(d锟斤拷ng)n≥35锟絩(sh锟斤拷),tn=|a1|+|a2|+…+|an|=(a1+a2+…+a34)-(a35+a36+…+an)=2(a1+a2+…+a34)-(a1+a2+…+an)=2s34-sn

锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷(x锟斤拷)锟斤拷1锟斤拷一锟斤拷(g锟斤拷)锟饺差數(sh锟斤拷)锟斤拷前4锟�(xi锟斤拷ng)锟侥猴拷锟斤拷24锟斤拷前5锟�(xi锟斤拷ng)锟侥猴拷锟絚前2锟�(xi锟斤拷ng)锟侥和的诧拷锟斤拷27锟斤拷锟斤拷锟紷锟斤拷(g锟斤拷)锟饺差數(sh锟斤拷)锟叫碉拷通锟�(xi锟斤拷ng)锟斤拷式.2锟斤拷锟缴傦拷(g锟斤拷)锟斤拷(sh锟斤拷)锟斤拷1,,,……,,5锟斤拷1,,,……,,5锟斤拷锟缴等差數(sh锟斤拷)锟叫癸拷锟斤拷謩e锟斤拷,,锟斤拷锟絚锟斤拷值锟斤拷3锟斤拷锟节等差數(sh锟斤拷)锟斤拷{}锟斤拷,锟斤拷锟斤拷15,锟斤拷锟斤拷d锟斤拷3,锟斤拷(sh锟斤拷)锟斤拷{}锟斤拷前n锟�(xi锟斤拷ng)锟酵碉拷锟斤拷小值锟斤拷

锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟絀(y锟斤拷)锟斤拷锟絥锟絩(sh锟斤拷)p119锟斤拷(x锟斤拷)锟絵3.39锟斤拷10锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷p122锟斤拷锟斤拷锟絖(d锟斤拷)锟斤拷(bi锟斤拷o)訓(x锟斤拷n)锟斤拷.
 

       锟斤拷锟絇(gu锟斤拷n)锟斤拷锟絔锟斤拷

锟斤拷锟斤拷锟斤拷一锟斤拷(sh锟斤拷)锟絎(xu锟斤拷)锟教帮拷锟絉锟斤拷

锟斤拷锟斤拷锟斤拷一锟斤拷(sh锟斤拷)锟絎(xu锟斤拷)锟教帮拷锟斤拷锟斤拷(sh锟斤拷)锟紿锟斤拷锟絵锟侥猴拷锟斤拷(sh锟斤拷)锟教�锟�

锟斤拷锟铰高匡拷锟結訊锟斤拷锟竭匡拷锟斤拷锟斤拷锟斤拷锟斤拷前锟斤拷(zh锟斤拷n)锟斤拷锟斤拷志愿锟斤拷锟�(b锟斤拷o)锟斤拷锟饺★拷锟�?j锟斤拷n)?sh锟斤拷)锟斤拷锟斤拷

锟竭匡拷锟絩(sh锟斤拷)锟絞锟斤拷锟斤拷全锟斤拷锟斤拷要锟斤拷(ji锟斤拷)锟絚(di锟斤拷n)

锟組锟斤拷"锟竭匡拷锟絎(w锟斤拷ng)"微锟脚癸拷锟斤拷號(h锟斤拷o)