左平移2个单位:y=a(x-h+2)²+k;
再向上平移四个单位:y=a(x-h+2)²+k+4;
比较y=-1/2(x+1)²-1,可知:a=-1/2, h=1,k=-5;
所以原函数为:y=-1/2(x-1)²-5;开口向下,对称轴为x=1; 顶点坐标为(1,-5).
左平移2个单位:y=a(x-h+2)²+k;
再向上平移四个单位:y=a(x-h+2)²+k+4;
比较y=-1/2(x+1)²-1,可知:a=-1/2, h=1,k=-5;
所以原函数为:y=-1/2(x-1)²-5;开口向下,对称轴为x=1; 顶点坐标为(1,-5).