Sponsor Area

Continuity And Differentiability

Question
CBSEENMA12036226

If straight x dy over dx space equals space straight y space left parenthesis log space straight y space minus space log space straight x space plus 1 right parenthesis commathen the solution of the equation is

  • straight y space log space open parentheses straight x over straight y close parentheses space equals cx
  • space straight x space log space open parentheses straight y over straight x close parentheses space equals space cy
  • log space open parentheses straight y over straight x close parentheses space equals space cx
  • log space open parentheses x over y close parentheses space equals space cx

Solution

C.

log space open parentheses straight y over straight x close parentheses space equals space cx fraction numerator straight x space dy over denominator dx end fraction space equals space straight y space left parenthesis log space straight y space minus space log space straight x plus 1 right parenthesis
dy over dx space equals space straight y over straight x open parentheses log open parentheses straight y over straight x close parentheses plus 1 close parentheses
put space straight y space equals vx
dy over dx space equals space straight v plus space xdv over dx
rightwards double arrow space straight v space plus xdv over dx space equals space straight v space left parenthesis log space straight v plus 1 right parenthesis
xdv over dx space equals space straight v space log space straight v
rightwards double arrow space fraction numerator dv over denominator straight v space log space straight v end fraction space equals space dx over straight x
put space log space straight v equals space straight z
1 over straight v space dv space equals space dz
rightwards double arrow dz over straight z space equals space dx over straight x
In space straight z space equals space In space straight x space plus In space straight c
straight z space equals cx
log space straight v space equals space cx
log space open parentheses straight y over straight x close parentheses space equals cx

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