x2+(y+3)2 |
x2+(y?3)2 |
它的幾何意義是動點(diǎn)P(x,y)到定點(diǎn)(0,-3)與到定點(diǎn)(0,3)的距離之和為10>6,
從而軌跡為橢圓,焦點(diǎn)在y軸上,
且 a=5,c=3,∴b=4,
其標(biāo)準(zhǔn)方程為:
x2 |
16 |
y2 |
25 |
故選C.
x2+(y+3)2 |
x2+(y?3)2 |
x2 |
25 |
y2 |
16 |
x2 |
25 |
y2 |
9 |
x2 |
16 |
y2 |
25 |
x2 |
9 |
y2 |
25 |
x2+(y+3)2 |
x2+(y?3)2 |
x2 |
16 |
y2 |
25 |