已知抛物线C的顶点是椭圆M:X2/4+Y2/3=1的中心,焦点为椭圆M的右焦点.⑴求抛物线C的标准方程⑵若直线L过抛物线
4个回答

(1)由椭圆M:x²/2²+y²/(√3)²=1

∵a=2, b=√3, ∴c²=a²-b²=4-3=1

∴c=1. ∵p/2=c, ∴p=2,

由抛物线C:y²=2px,∴y²=4x.

(2)由L过(1,0),y=k(x-1),

联立y²=4x,y=kx-k,

k²x²-(k²+2)x+k²=0,

x1+x2=(k²+2)/k²,

x1x2=k²/k²=1

|x1-x2|=√[(x1+x2)²-4x1x2]=√[(16k²+16)/k^4]

|AB|=√(1+k²)(x1-x2)

=√(1+k²)16(1+k²)/k^4

=4(1+k²)/k²=8

k²=1

k=±1

y=x-1

或者y=-x+1.