Differential Equations Question 70
Question: The differential equation $ \cot ydx=xdy $ has a solution of the form
[Orissa JEE 2002]
Options:
A) $ y=\cos x $
B) $ x=c\sec y $
C) $ x=\sin y $
D) $ y=\sin x $
Show Answer
Answer:
Correct Answer: B
Solution:
$ \cot y.dx=x.dy $
Therefore $ \frac{dx}{x}=\frac{dy}{\cot y} $
Therefore $ \frac{dx}{x}=\tan y.dy $
Integrating both sides, $ \log x=\log \sec y+\log c $
Therefore $ x=c\sec y $ .
BETA
