(x1一x2)的绝对值
\u7edd\u5bf9\u503cx1-x2\u7b49\u4e8e\u4ec0\u4e48x1+x2=-b/a
x1x2=c/a
\u6240\u4ee5(x1-x2)²=(x1+x2)²-4x1x2
=b²/a²-4c/a
=(b²-4ac)/a²
\u6240\u4ee5|x1-x2|=\u221a(b²-4ac)/|a|
IX1\uff0d2I<1\uff0c-1<x1-2<1 1<x1<3
IX2-2I<1, -1<x2-2<1 1<x2<3
\u6240\u4ee5-2<x1-x2<2
\u6545Ix1-x2I<2
绛旓細x1鈥攛2鐨勭粷瀵瑰绛変簬鏍瑰彿涓锛坸1+x2锛夌殑骞虫柟鈥4x1x2鐒跺悗甯﹀叆鏃㈠彲銆
绛旓細闊﹁揪鍏紡鐨勮繍鐢 x1-x2鐨勭粷瀵瑰涓鍏冧簩娆℃柟绋嬩腑浠ｈ〃涓や釜鏍瑰湪鏁拌酱涓婄殑璺濈锛屽洜涓锛圶1+X2锛^2-4X1*X2=X1^2+X2^2-2X1*X2=(x1-x2)^2 鎵浠ュ氨鐢▅(x1-x2)|=(锛圶1+X2锛塣2-4X1*X2)^1/2 鍐嶇粨鍚堥煢杈惧畾鐞嗘潵姹傚嚭x1-x2鐨勭粷瀵瑰 ...
绛旓細瑙:鈭祒1锛寈2婊¤冻缁濆鍊硷紙X1-X2锛=鈭5,鈭(x1-x2)^2=5,鈭祒1.x2骞冲潎鏁版槸x=(x1+x2)/2.鈭存柟宸=[(x1-x)^2+(x2-x)^2]/2 =[(x1-x2)^2/4+(x2-x1)^2/4]/2 =[2(x1-x2)^2/4]/2 =(x1-x2)^2/4 =5/4
绛旓細鍥犱负 锛坸1+x2锛夌殑骞虫柟-4x1x2=(x1鐨勫钩鏂+x2鐨勫钩鏂+2x1x2)-4x1x2=x1鐨勫钩鏂+x2鐨勫钩鏂-2x1x2=(x1-x2)鐨骞虫柟
绛旓細涓鍏冧簩娆℃柟绋媋x²+bx+c=0(a鈮0)x1+x2=-b/a x1*x2=c/a |x1-x2|=鈭(x1-x2)²=鈭歔(x1+x2)²-4x1x2]=鈭(b²/a²-4c/a)=[鈭(b²-4ac)]/|a|
绛旓細搴旇绛変簬鏍瑰彿寰峰皵濉旈櫎浠鍚
绛旓細瑙ｏ細鍥犱负涓嶈В鏂圭▼ 鎵浠x1-x2=卤2锛堚垰锛坆�0�5-4ac锛夛級/锛2a锛=卤锛堚垰锛坆�0�5-4ac锛夛級/锛坅锛=卤锛堚垰锛25+4脳1脳8锛夛級/1 =卤鈭57 鎵浠1-x2=卤鈭57 浜诧紝璇锋偍閲囩撼锛屾偍鐨勯噰绾虫槸鎴戠殑鍔ㄥ姏锛岃阿璋
绛旓細|(鏍瑰彿(b^2-4ac))/a|
绛旓細x1➖x2鐨勭粷瀵瑰鏄粈涔 =鈭(x1-x2)²=鈭歔(x1+x2)²-4x1x2]=鈭(b²-4ac) /|a|
绛旓細鎬ユ眰!!涓轰粈涔坸1-x2鐨勭粷瀵瑰=鏍瑰彿涓(x1+x2)鐨骞虫柟-4x1x2涓昏鏄牴鍙蜂笅鐨勯儴鍒嗗叿浣撴槸鎬庝箞鏉ョ殑,璋㈣阿鍟!1涓洖绛 #鐑# 鑱屽満涓婂彈濮斿眻瑕佷笉瑕佷负鑷繁瑙ｉ噴?feng123h0 2013-12-21 路 TA鑾峰緱瓒呰繃6125涓禐 鐭ラ亾澶ф湁鍙负绛斾富 鍥炵瓟閲:2849 閲囩撼鐜:100% 甯姪鐨勪汉:2159涓 鎴戜篃鍘荤瓟棰樿闂釜浜洪〉 鍏虫敞 ...
