设P(x,y)到定点的距离为d
d²=(x-1)²+y²
由椭圆方程得:y²=4-4x²/9
所以:
d²=(x-1)²+4-4x²/9
=5x²/9-2x+5
=5/9*(x-9/5)²+16/5
当x=9/5时,d²最小,为16/5
所以d_min=(4/5)√5
设P(x,y)到定点的距离为d
d²=(x-1)²+y²
由椭圆方程得:y²=4-4x²/9
所以:
d²=(x-1)²+4-4x²/9
=5x²/9-2x+5
=5/9*(x-9/5)²+16/5
当x=9/5时,d²最小,为16/5
所以d_min=(4/5)√5