设A(x1,y1),B(x2,y2)是抛物线y2=2px(p>0)上两点,且满足OA⊥OB,则y1y2等于_.
问题描述:
设A(x1,y1),B(x2,y2)是抛物线y2=2px(p>0)上两点,且满足OA⊥OB,则y1y2等于______.
答
∵A(x1,y1),B(x2,y2)是抛物线y2=2px(p>0)上的两点,并且满足OA⊥OB.
∴kOA•kOB=-1,∴x1x2+y1y2=0,∴
+y1y2=0,(y1y2)2
4p2
则y1y2=-4p2
故答案为:-4p2.