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The solution of the differential equation log⁡e(dydx)=5x+2y\log_e\left(\frac{dy}{dx}\right) = 5x + 2y is given by

Solution

✅ Correct Option: 2

Given:

log⁡e(dydx)=5x+2y\log_e\left(\frac{dy}{dx}\right) = 5x + 2y


Apply ee to both sides:

elog⁡e(dydx)=e5x+2ye^{\log_e\left(\frac{dy}{dx}\right)} = e^{5x + 2y}

dydx=e5x+2y\frac{dy}{dx} = e^{5x + 2y}


Using ea+b=ea⋅ebe^{a+b} = e^a \cdot e^b:

dydx=e5x⋅e2y\frac{dy}{dx} = e^{5x} \cdot e^{2y}


Separating variables:

dye2y=e5x dx\frac{dy}{e^{2y}} = e^{5x} \, dx

e−2y dy=e5x dxe^{-2y} \, dy = e^{5x} \, dx


Integrating both sides:

∫e−2y dy=∫e5x dx\int e^{-2y} \, dy = \int e^{5x} \, dx

−12e−2y=e5x5+C1-\frac{1}{2}e^{-2y} = \frac{e^{5x}}{5} + C_1


Multiplying both sides by −10-10:

5e−2y=−2e5x−10C15e^{-2y} = -2e^{5x} - 10C_1

2e5x+5e−2y=−10C12e^{5x} + 5e^{-2y} = -10C_1

Since −10C1-10C_1 is an arbitrary constant, let C=−10C1C = -10C_1:

2e5x+5e−2y+C=02e^{5x} + 5e^{-2y} + C = 0

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