The solution of the differential equation $x^3\frac{dy}{dx}+4x^2 tan\, y = e^xsec\, y $ satisfying $y(1) = 0,$ is |
$tan\, y = (x-2) e^x log x$ $sin \, y =e^x (x-1) x^{-4}$ $tan\, y = (x-1)e^x x^{-3}$ $sin y = e^x (x-1)x^{-3}$ |
$sin \, y =e^x (x-1) x^{-4}$ |
The correct answer is option (2) : $sin \, y =e^x (x-1) x^{-4}$ $x^3\frac{dy}{dx}+4x^2 tan\, y = e^xsec\, y $ $⇒x^3cos\, y \frac{dy}{dx}+4x^2 sin y = e^x$ $⇒x^4 \, cos \, y \, dy + 4x^3 \, sin y \, dx = xe^x\, dx $ $⇒d(x^4 \, sin y ) = xe^x + dx$ On integrating, we get $x^4sin\, y = (x-1) e^x+C$ It is given that $y = 0 $ where $x= 1.$ Putting $x=1$ and $y = 0 $ in (i), we get $C+0$ Putting $C=0 $ in (i), we get $x^4 sin\, y (x-1) e^x ⇒ sin\, y = e^x (x-1)x^{-4}$ |