《九年級(jí)數(shù)學(xué)上冊 第二十三章《旋轉(zhuǎn)》23.2 中心對(duì)稱 23.2.3 關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)課件 （新版）新人教版》由會(huì)員分享，可在線閱讀，更多相關(guān)《九年級(jí)數(shù)學(xué)上冊 第二十三章《旋轉(zhuǎn)》23.2 中心對(duì)稱 23.2.3 關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)課件 （新版）新人教版（9頁珍藏版）》請(qǐng)?jiān)谘b配圖網(wǎng)上搜索。

1、23.2.3關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)知識(shí)要點(diǎn)基礎(chǔ)練知識(shí)點(diǎn)1關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)特征 2.已知點(diǎn)P1( -4,3 )和P2( -4,-3 ),則P1和P2 ( C )A.關(guān)于原點(diǎn)對(duì)稱B.關(guān)于y軸對(duì)稱C.關(guān)于x軸對(duì)稱D.不存在對(duì)稱關(guān)系3.ABC三個(gè)頂點(diǎn)的坐標(biāo)依次為A( 1,-1 ),B( 4,1 )和C( 2,2 ),將ABC繞坐標(biāo)原點(diǎn)旋轉(zhuǎn)180,旋轉(zhuǎn)后所得三角形各頂點(diǎn)的坐標(biāo)依次為( -1,1 ),( -4,-1 ),( -2,-2 ).知識(shí)要點(diǎn)基礎(chǔ)練知識(shí)點(diǎn)2關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)的應(yīng)用4.坐標(biāo)平面內(nèi)有兩點(diǎn)P( x,y ),Q( m,n ),若x+m=0,y+n=0,則點(diǎn)P與點(diǎn)Q ( C )A.關(guān)

2、于x軸對(duì)稱B.關(guān)于y軸對(duì)稱C.關(guān)于原點(diǎn)對(duì)稱D.無對(duì)稱關(guān)系5.在平面直角坐標(biāo)系中,若點(diǎn)P( m,m-n )與點(diǎn)Q( -4,5 )關(guān)于原點(diǎn)對(duì)稱,則點(diǎn)M( m,n )的坐標(biāo)為 ( B )A.( 2,5 )B.( 4,9 )C.( 3,-2 )D.( 3,2 )6.若點(diǎn)P( a-5,a+3 )關(guān)于原點(diǎn)對(duì)稱的點(diǎn)在第四象限,則a的取值范圍為-3a3B.0a3C.a0D.a3綜合能力提升練10.在平面直角坐標(biāo)系中,若點(diǎn)P( x,y )在第二象限,且|x|-1=0,y2-4=0,則點(diǎn)P關(guān)于坐標(biāo)原點(diǎn)對(duì)稱的點(diǎn)P的坐標(biāo)是 ( B )A.P( -1,-2 )B.P( 1,-2 )C.P( -1,2 )D.P( 1,2

3、 )11.若點(diǎn)A( -3,n )在x軸上,則點(diǎn)B( n-1,n+1 )關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)為( 1,-1 ).12.若點(diǎn)A( 3-m,2 )在函數(shù)y=2x-4的圖象上,則點(diǎn)A關(guān)于原點(diǎn)對(duì)稱的點(diǎn)的坐標(biāo)是( -3,-2 ).綜合能力提升練14.如圖,已知A( 2,3 )和直線y=x.( 1 )分別寫出點(diǎn)A關(guān)于直線y=x的對(duì)稱點(diǎn)B和關(guān)于原點(diǎn)的對(duì)稱點(diǎn)C的坐標(biāo).( 2 )若點(diǎn)D是點(diǎn)B關(guān)于原點(diǎn)的對(duì)稱點(diǎn),判斷四邊形ABCD的形狀,并說明理由.解:( 1 )點(diǎn)A關(guān)于直線y=x的對(duì)稱點(diǎn)B和關(guān)于原點(diǎn)的對(duì)稱點(diǎn)C的坐標(biāo)分別為B( 3,2 ),C( -2,-3 ).( 2 )四邊形ABCD是矩形.理由如下:B( 3,2 )關(guān)于原點(diǎn)的對(duì)稱點(diǎn)為D( -3,-2 ),又點(diǎn)B和點(diǎn)D關(guān)于原點(diǎn)對(duì)稱,BO=DO.同理AO=DO,四邊形ABCD是平行四邊形.A關(guān)于直線y=x的對(duì)稱點(diǎn)為B,點(diǎn)A關(guān)于原點(diǎn)的對(duì)稱點(diǎn)C,AC=BD,四邊形ABCD是矩形.綜合能力提升練綜合能力提升練拓展探究突破練17.如圖所示,在平面直角坐標(biāo)系中,點(diǎn)P( 1,0 )作如下實(shí)驗(yàn):先向上平移( 后一次平移比前一次多1個(gè)單位長度 ),再作關(guān)于原點(diǎn)的對(duì)稱點(diǎn),即向上平移1個(gè)單位得到點(diǎn)P1,作點(diǎn)P1關(guān)于原點(diǎn)的對(duì)稱點(diǎn)P2,再向上平移2個(gè)單位得到P3,作P3關(guān)于原點(diǎn)的對(duì)稱點(diǎn)P4,那么點(diǎn)P2015的坐標(biāo)是( -1,504 ).