The length of the latus-rectum of the parabola y2+8x−2y+17=0 is
2
4
8
16
Given: y2+8x−2y+17=0
⇒ (y−1)2−1+8x+17=0 ⇒ (y−1)2+8x+16=0
⇒ (y−1)2=−8(x+2)
Let X=x+2,Y=y-1
∴ Y2=−8X
Comparing with y2=4ax:
a=2
Length of the latus rectum =4a=8 units.
Latus rectum of the parabola y2−4y−2x−8=0 is