锟斤拷锟斤拷锟节诧拷锟斤拷式锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷(j锟斤拷ng)锟斤拷锟芥及锟斤拷锟斤拷锟斤拷锟斤拷e锟斤拷锟絯锟絜锟饺ｏ拷也锟芥及某些锟斤拷(sh锟斤拷)锟絎锟斤拷锟斤拷(锟界實锟斤拷(sh锟斤拷)锟斤拷锟斤拷锟斤拷)锟侥达拷小锟斤拷^锟斤拷值锟斤拷锟紽(xi锟斤拷n)锟截準傦拷锟剿絕锟斤拷值锟斤拷锟斤拷式知锟絉锟絚锟侥冿拷(n锟斤拷i)锟斤拷锟斤拷

锟斤拷锟斤拷锟斤拷式锟斤拷|a|-|b|≤|a+b|≤|a|+|b|

锟斤拷锟斤拷锟斤拷锟絴(zh锟斤拷)

锟斤拷锟斤拷|a|锟斤拷示锟斤拷(sh锟斤拷)锟絊锟较碉拷锟絚a锟絚原锟絚锟侥撅拷锟絰锟斤拷锟斤拷锟斤拷(sh锟斤拷)a锟侥絕锟斤拷值锟斤拷

锟斤拷锟斤拷锟缴傦拷锟斤拷要锟斤拷锟絴(zh锟斤拷)锟斤拷1.|ab|=|a||b|;|a/b|=|a|/|b|

锟斤拷锟斤拷2.|a|<|b|锟斤拷锟斤拷a2

锟斤拷锟斤拷锟斤拷锟斤拷

锟斤拷锟斤拷|a|-|b|≤|a+b|≤|a|+|b|锟斤拷锟斤拷锟揭僅锟斤拷ab≤0锟絩锟斤拷邊锟斤拷號锟斤拷锟斤拷锟斤拷ab≥0锟絩锟斤拷邊锟斤拷號锟斤拷锟斤拷锟斤拷

锟斤拷锟斤拷|a|-|b|≤|a-b|≤|a|+|b|锟斤拷锟斤拷锟揭僅锟斤拷ab≥0锟絩锟斤拷邊锟斤拷號锟斤拷锟斤拷锟斤拷ab≤0锟絩锟斤拷邊锟斤拷號锟斤拷锟斤拷锟斤拷

锟斤拷锟斤拷锟阶猴拷锟斤拷锟絰

锟斤拷锟斤拷1.锟斤拷a锟斤拷b同號锟絩锟斤拷锟斤拷位锟斤拷原锟絚锟斤拷同一邊锟斤拷锟剿時a锟絚锟斤拷b锟侥撅拷锟絰锟斤拷锟斤拷锟斤拷锟斤拷锟斤拷原锟絚锟侥撅拷锟絰之锟斤拷锟斤拷2.锟斤拷a锟斤拷b锟斤拷號锟絩锟斤拷锟斤拷锟街別位锟斤拷原锟絚锟侥冿拷邊锟斤拷锟剿時a锟絚锟斤拷b锟侥撅拷锟絰小锟斤拷锟斤拷锟斤拷锟斤拷原锟絚锟侥撅拷锟絰之锟斤拷锟斤拷

锟斤拷锟斤拷(|a+b|锟斤拷示a-b锟絚原锟絚锟侥撅拷锟絰锟斤拷也锟斤拷示a锟絚b之锟絞锟侥撅拷锟絰)

锟斤拷锟斤拷锟絕锟斤拷值锟斤拷要锟斤拷锟斤拷式

锟斤拷锟斤拷锟揭傦拷知锟斤拷

锟斤拷锟斤拷|a|={a锟斤拷(a>0)锟斤拷a锟斤拷(a=0)锟斤拷锟斤拷a锟斤拷(a<0)锟斤拷}

锟斤拷锟斤拷锟斤拷耍锟斤拷锟�

锟斤拷锟斤拷锟斤拷|a|≤a≤|a|

锟斤拷锟斤拷锟斤拷|b|≤b≤|b|

锟斤拷锟斤拷同锟接碉拷

锟斤拷锟�锟斤拷伲锟斤拷锟斤拷锟接碉拷

锟斤拷锟斤拷锟斤拷锟絭|a|+|b|)≤a+b≤|a|+|b|

锟斤拷锟斤拷锟斤拷|a+b|≤|a|+|b|

锟斤拷锟斤拷锟紷锟斤拷锟斤拷見锟斤拷a锟斤拷b同號锟斤拷锟斤拷一锟斤拷锟斤拷0锟絩锟斤拷锟斤拷式锟斤拷號锟斤拷锟斤拷锟斤拷

锟斤拷锟斤拷锟缴③可碉拷

锟斤拷锟斤拷|a|=|(a+b)-b|≤|a+b|+|-b|锟斤拷

锟斤拷锟斤拷锟斤拷|a|-|b|≤|a+b|

锟斤拷锟斤拷锟紺锟较�锟�锟斤拷锟斤拷锟揭傦拷锟矫碉拷锟斤拷锟絇锟絕锟斤拷值(absolutevalue)锟斤拷锟斤拷要锟斤拷锟斤拷式

锟斤拷锟斤拷|a|-|b|≤|a+b|≤|a|+|b|

锟斤拷锟絇锟斤拷锟絔锟斤拷

锟斤拷锟斤拷锟竭匡拷锟斤拷(sh锟斤拷)锟絎知锟絉锟絚锟絉锟斤拷

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绞傦拷锟斤拷志愿锟斤拷锟�锟斤拷锟饺★拷謹锟�(sh锟斤拷)锟斤拷锟斤拷

锟竭匡拷锟絩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

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