Sponsor Area

Conic Section

Question
CBSEENMA11015587

The differential equation of all circles passing through the origin and having their centres on the x-axis is

  • straight x squared space equals straight y squared space plus space xy dy over dx
  • straight x squared space equals straight y squared space plus space 3 xy dy over dx
  • straight x squared space equals straight y squared space plus space 2 xy dy over dx
  • straight x squared space equals straight y squared space minus space 2 xy dy over dx

Solution

C.

straight x squared space equals straight y squared space plus space 2 xy dy over dx

General equation of all such circles is
x2+ y2 + 2gx = 0.
Differentiating, we get
2 straight x space plus 2 straight y space dy over dx space plus 2 straight g space equals space 0
therefore space Desired space equation space is
straight x squared space plus space straight y squared space plus space open parentheses negative 2 straight x minus 2 straight y dy over dx close parentheses space straight x space equals space 0
rightwards double arrow straight y squared space equals space straight x squared space plus space 2 xy dy over dx