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6.17 Solution

On integrating, we have

ex2⁢y=∫x⁢ex2⁢d⁢xe^{x^{2}}y=\int xe^{x^{2}}\,dx

which equals 12⁢ex2+c\frac{1}{2}e^{x^{2}}+c. Dividing both sides by ex2e^{x^{2}}, we obtain solutions y=12+c⁢e-x2y={\frac{1}{2}+ce^{-x^{2}}} where cc is an arbitrary constant.

Let’s verify that this gives a solution of the equation: we have d⁢yd⁢x=-2⁢c⁢x⁢e-x2,\frac{dy}{dx}={-2cxe^{-x^{2}},} so

d⁢yd⁢x+2⁢x⁢y=-2⁢c⁢x⁢e-x2+x+2⁢x⁢c⁢e-x2=x\frac{dy}{dx}+2xy={-2cxe^{-x^{2}}+x+2xce^{-x^{2}}=x}

as required.