Differential Equations Question 346

Question: The solution of the differential equation $ (1+\cos x)dy=(1-\cos x)dx $ is

Options:

A) $ y=2\tan \frac{x}{2}-x+c $

B) $ y=2\tan x+x+c $

C) $ y=2\tan \frac{x}{2}+x+c $

D) $ y=x-2\tan \frac{x}{2}+c $

Show Answer

Answer:

Correct Answer: A

Solution:

Here $ \frac{dy}{dx}=\frac{1-\cos x}{1+\cos x}={{\tan }^{2}}\frac{x}{2} $

Therefore $ dy=( {{\sec }^{2}}\frac{x}{2}-1 )dx $

Now on integrating both the sides, we get $ y=2\tan \frac{x}{2}-x+c $ .