1.

The integrating factor of differential equation `(dy)/(dx)+y=(1+y)/(x)"is"`A. `(x)/(x^(x)`B. `(e^(x))/(x)`C. `xe^(x)`D. `e^(x)`

Answer» Given that, `" "(dy)/(dx)+y=(1+y)/(x)`
`rArr" "(dy)/(dx)=(1+y)/(x)-y`
`rArr" "(dy)/(dx)=(1+y-xy)/(x)`
`rArr" "(dy)/(dx)=(1)/(x)+(y(1-x))/(x)`
`rArr" "(dy)/(dx)-((1-x)/(x))y=(1)/(x)`
Here, `" "P=(-(1-x))/(x),Q=(1)/(x)`
`" "IF=e^(intPdx)=e^(-int(1-x)/(x)dx)=e^(int(x-1)/(x)dx)`
`" "=e^(int(1-(1)/(x))dx`
`" "e^(intx-logx)`
`" "=e^(x)*e^(log((1)/(x)))`
`" "=e^(x)*(1)/(x)`


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