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The integrating factor of the differential equation, x2dydx+xy=logexx^2 \frac{dy}{dx} + xy = log_e x is equal to

Solution

✅ Correct Option: 3

The differential equation is x2dydx+xy=log⁡exx^2 \frac{dy}{dx} + xy = \log_e x.

The standard form of a linear differential equation is:

dydx+P(x)⋅y=Q(x)\frac{dy}{dx} + P(x) \cdot y = Q(x)

Dividing the entire equation by x2x^2:

dydx+yx=log⁡exx2\frac{dy}{dx} + \frac{y}{x} = \frac{\log_e x}{x^2}


Comparing with the standard form dydx+P(x)⋅y=Q(x)\frac{dy}{dx} + P(x) \cdot y = Q(x):

P(x)=1xP(x) = \frac{1}{x}


The integrating factor formula is:

I.F.=e∫P(x)dx\text{I.F.} = e^{\int P(x)dx}

Substituting P(x)=1xP(x) = \frac{1}{x}:

I.F.=e∫1xdx\text{I.F.} = e^{\int \frac{1}{x}dx}


Since ∫1xdx=log⁡ex\int \frac{1}{x}dx = \log_e x:

I.F.=elog⁡ex\text{I.F.} = e^{\log_e x}

Using the property elog⁡ex=xe^{\log_e x} = x:

I.F.=x\text{I.F.} = x


Therefore, the integrating factor is xx.

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