1.

Maximum number of common normals of `y^2=4ax and x^2=4by` is ____A. 3B. 4C. 6D. 5

Answer» Correct Answer - D
(4) Normal to `y^(2)=4axandx^(2)=4by` in terms of m are
`y=mx-2am-am^(3)`
`andy=mx+2b+(b)/(m^(2))`
For a common normal,
`2b+(b)/(m^(2))+2am+am^(3)=0`
`oram^(5)+2am^(3)+2bm^(2)+b=0`
This means there can be at most five common normals


Discussion

No Comment Found

Related InterviewSolutions