Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section A

Chapter

Differential Equations

Question:

Find the general solution of the DE :

\(\frac{dy}{dx}\) = \(\frac{1+y^2}{1+x^2}\)

Options:

\(\tan^{-1} {x}\) = \(\tan^{-1} {y}\) + C

\(\tan^{-1} {x}\) - \(\tan^{-1} {y}\) = C

\(\tan^{-1} {y}\) = \(\tan^{-1} {x}\) + C

All the above

Correct Answer:

All the above

Explanation:

\(\frac{dy}{dx}\) = \(\frac{1+y^2}{1+x^2}\)

dx . 1+x= dy . 1+y and then integrate to get : 

\(\tan^{-1} {x}\) = \(\tan^{-1} {y}\) + C , or

\(\tan^{-1} {y}\) = \(\tan^{-1} {x}\) + C, or

\(\tan^{-1} {x}\) - \(\tan^{-1} {y}\) = C

Note : -ve sign can be incorporated into the constant C