The solution of differential equation dydx+2xy1+x2=1(1+x2)2 is
(a) y(1+x2)=C+tan−1x
(b) y1+x2=C+tan−1x
(c) ylog(1+x2)=C+tan−1x
(d) y(1+x2)=C+sin−1x
Given that, dydx+2xy1+x2=1(1+x2)2
Here, P=2x1+x2 and Q=1(1+x2)2
which is a linear differential equation.
∴IF=e∫2x1+x2dx
Put 1+x2=t⇒2xdx=dt∴IF=e∫dtt=elogt=elog(1+x2)1+x2
The general solution is
y.(1+x2)=∫(1+x2)1(1+x2)2+C⇒y(1+x2)=∫11+x2dx+C⇒y(1+x2)=tan−1x+C