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Solve x dy/dx + y log y = xy eˣ

Short answer

Divide by xy, set z=log y to obtain dz/dx + z/x = eˣ. Integrating factor x gives xz = (x−1)eˣ + c. Hence x log y = (x−1)eˣ + c.

Solve the differential equation x dy/dx + y log y = xy eˣ.

x dy/dx + y log y = xy eˣ

Reduce to a linear equation

Divide by xy:

(1/y) dy/dx + (log y)/x = eˣ

Put z = log y, so dz/dx = (1/y) dy/dx:

dz/dx + z/x = eˣ

This is linear in z with P = 1/x, Q = eˣ.

Integrating factor

IF = e^(∫dx/x) = x

Solution

z · x = ∫ x eˣ dx = x eˣ − eˣ + c = (x − 1)eˣ + c

Replace z = log y:

x log y = (x − 1)eˣ + c, i.e. log y = (1 − 1/x)eˣ + c/x.

✓ Answer checked by Claude Opus 5.5 (high effort)

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