第18期 为什么要证明&定义与命题-2018-2019学年八年级上册数学【中学生理化报】北师大

!"#$%& ' !"#$#%& ( ! !" " #$! #$%&'( !" #" $" %" &" '" ("!"" )"#!$%&!'()*+,-*. #$/%&"'0123 ! 4 "567. 8&/%&#'*-2 #$ 4-2 %& 9:' *! %&!'*;<=>?@ ( ; + , " , + *(8-. $ /" %&"'*7<=>?@ ( 7 + !& " ) + *)8-. $ /" A@ ( ; ! ( 7 B CDEFGHIB%&!'*;<=JKLH%&" '*7<=" %$& )*+,-.'/ !" '" $" '" &" #" (" #" )"M.NOGP5BQ ! + !B" + /" *"0RSTUBV0RS,WXS" 0! !"#" ,"#!/QY01-29:Z[51-2B\]V01 -29:. #$/QY0RS,[5RS*^SB\]V0RSTU. 8&/QY0R_*`WaTUB\]V0R_5bTU" 1"8!/Mc%Bdef! 2 3 $Bg 3 $ 2 ! . 8$/hc%. 8&/Mc%Bdef&/#S*^S, */$*SBiZ &/$ Sjk4 %$& 0*+,-.&1 !5 #" $" %" &" '" (" 0-29:B[lmSno.Upqr.[lmSn oB0-29:" )" % ")%$ + 16$8st$B & "* + ", + 16$8-SuS=*0RvSn $̂5 ! %&#*,8st$B & ",&% + 16$8w-*bx$5 &"&%, +", + 16$8-SuS=*0RvSn $̂5 & "* - "&%,8[S*^STU$5 *5 % "! + "$8st$B & #&$,.8m!STUB0-29:$5 & "& + "&,.80-29:Bm!STU$5 % "& + "&8st$B & "& + "&,.8Upqr$5 & ,&$%.8m!STUB0-29:$5 %$!(%$& 23- 456789:4;0< !5 75 $5 #5 &5 '5 (5 %5 )5 %5 *5 75 05 75 ,5 '5 =5>?@A:BCDE 15"5 !65 QYy5z{st-2*w2B \]V6*w2 |}~|515 !!5,.G,5 !$5 &5 !&5 !&6$5 !(5"$5 F5GHIJ:KLMN !)5#!/QY0R_@[�B\]V0R_*�5bG ,�_5Mc%Bdef#8 !/9#8 $/+ 8 &. #$/QY / $ 8 $ + /B\] / + $ % 4 Mc%Bdef/ + 8 $ % . #&/QY0R_n@�_B\]V0R_*?@ !4 h c%4 !*4G;�!��deQ�f ��5f� 0 + 0 �B0 $ 8 *0 + 0 ' /B & ��*E�G;�4 ���f0 $ 8 *0 + 0#0 8 */B� 0& *�B0 8 *& /B & 0 $ 8 *0& /! & ��*E�G;�4 !04#!/"$1&B"*12. #$/% ",12 :"21& + $ : &B & "21& ( & $ ",12" � %"&1, +"*1% + 06$B"&1, +",12 9"21&B ) ",12 + & $ ",12 ( 06$" & ",12 + $,$" & "*12 + !,6$ * ",12 + !)$$" !,"NOGP5BQ!"# '$B ��"! + "$B"& + ",B.3(*, Zz 3B � %&) *, Zz &" ��Q�f+ "& + ",#st/B & &2*,%#[�STUB0-29:/" & "! + ",%&#0-29:Bm!STU/" % "! + "$#st/B & "$ + ",%&#Upqr/" & 3.*%&#[�STUB0-29:/" & "%&, + ",3.#0-29:B[�STU/" % .3)*,#st/B & ",3. + 16$#w-*bx/" & "%&, + 16$#Upqr/B � %&)*,#w-*bx/" !1"#!/1�,f!".��,f#" #$/��Q�f �+*,2 4+&%2 'B "*2, 4 "&2%B "# - "&B #, - &% , . . . - . . . / B " +#,2 !+&%2#77;/5 " $2 - 2%' 9O-.PQRS1 #" $8 8 $$ ! " # $ ! " # $ % & ! " # $ % & ' ( ) * $ + % , - . / !"#$%&'()*+, ! " # $ % & ' ( 0 1 2 3 4 5 ! ) * + , - . / 0 !" !!"!#$%&'()* !+,-.$