- Exam
- JEE Main
- Year
- 2023
- Date
- 15 April
- Shift
- Morning Shift
- Subject
- Mathematics
- Chapter
- Differential Equations
JEE Main 2023 · 15 April · Morning Shift · Mathematics · Differential Equations
Let x = x (y) be the solution of the differential equation 2(y + 2)...
Options
- A
- B
- C
- D
Correct answer
C.
Step-by-step solution
Given,
Let
So, the equation becomes,
\left(2vlnv\right)du = - \left(u - 2\ln v\right)dv⇒ 2vlnv\dfrac{du}{dv} + u = 2\ln v⇒ \dfrac{du}{dv} + \dfrac{1}{2vlnv} . u = \dfrac{1}{v}IF = {e}^{\dfrac{1}{2} ∫ \dfrac{1}{vlnv}} = {e}^{\dfrac{1}{2}\ln \left(\ln v\right)} = \left(\ln v\right)\dfrac{1}{2}u \cdot \left(\ln v\right)\dfrac{1}{2} = ∫ \dfrac{1}{v} \cdot \left(\ln v\right)\dfrac{1}{2}dv⇒ u \cdot \left(\ln v\right)\dfrac{1}{2} = \dfrac{2}{3}\left(\ln v\right)\dfrac{3}{2} + c . . . . . . . \left(i\right)y = {e}^{4} - 2 ⇒ x = 1∴ v = {e}^{4} ⇒ u = 55 \cdot \left(4\dfrac{1}{2}\right) = \dfrac{2}{3} \cdot \left(4\right)\dfrac{3}{2} + c⇒ 10 = \dfrac{16}{3} + c⇒ c = \dfrac{14}{3}y = {e}^{9} - 2 ⇒ v = y + 2 = {e}^{9} we get,