1.

The line `x+y=6` is normal to the parabola `y^(2)=8x` at the point.A. (4,2)B. (2,4)C. (2,2)D. (3,3)

Answer» Correct Answer - B
`y=-x+6` ..(1) is normal to `y^(2)=4ax` the of line (1)
Now equation of any normal to the parabola `y^(2)=4ax` is `y=mx-2am-am^(3)`
Comparing (1) and (2) we get
`mx=-ximpliesm=-1`
`6=-2am-am^(3)`
`6=-2a(-1)-a(-1)^(3)`
`6=2a+a=3aimpliesa=2`
`because` point `(am^(2),-2am)=(2(-1)^(2),-2xx2xx-1)=(2,4)`


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