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Recognise an exact product derivative

The variables satisfy xeydydx+ey=2xxe^y\dfrac{dy}{dx}+e^y=2x.

(i) Use z=xeyz=xe^y to obtain an equation relating zz and xx.

(ii) Hence, or otherwise, show that the general solution is y=ln⁡(x+k/x)y=\ln(x+k/x), where kk is arbitrary.

[2007/MJC/MYE/II/4(b)]

CJC · Discussion · Question 3

Look for the product derivative of x times eʸ.

Read the worked solution