①以點(diǎn)為圓心,的長為半徑作弧,交的延長線于點(diǎn);
②以點(diǎn)為圓心,取定長為半徑作弧分別交的兩邊于點(diǎn)、;
③以點(diǎn)為圓心,為半徑作弧,交于點(diǎn);
④以點(diǎn)為圓心,的長為半徑作弧,交前弧于點(diǎn) , 連接并延長交的延長線于點(diǎn) .
由作圖步驟①可得;
由作圖步驟②③④可得;
又因?yàn)?img class="mathml" src="http://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmrow%3E%3Cmo%3E%E2%88%A0%3C%2Fmo%3E%3Cmi%3EA%3C%2Fmi%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3EB%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmo%3E%E2%88%A0%3C%2Fmo%3E%3Cmi%3ED%3C%2Fmi%3E%3Cmi%3EC%3C%2Fmi%3E%3Cmi%3EE%3C%2Fmi%3E%3C%2Fmrow%3E%3C%2Fmath%3E" style="max-width:100%;vertical-align: middle;">:
所以 , 理由是.
①求點(diǎn)A的坐標(biāo)和n的值;
②將拋物線向上平移后的新拋物線與x軸的一個(gè)交點(diǎn)為D,頂點(diǎn)A移至點(diǎn) , 如果四邊形為平行四邊形,求平移后新拋物線的表達(dá)式;