题目

He is such a hypocritical person that you shouldn't believe all the news he told you. 答案：【1】that已知抛物线C：x2=4y，过焦点F的直线l与抛物线交于A，B两点（A在第一象限）．（Ⅰ）当S△OFA=2S△OFB时，求直线l的方程；（Ⅱ）过点A（2t，t2）作抛物线C的切线l1与圆x2+（y+1）2=1交于不同的两点M，N，设F到l1的距离为d，求|MN|d的取值范围．