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y-2x-y-2-4y-




Question Number 86294 by jagoll last updated on 28/Mar/20
y = 2x + (y′)^2 −4y′
$$\mathrm{y}\:=\:\mathrm{2x}\:+\:\left(\mathrm{y}'\right)^{\mathrm{2}} −\mathrm{4y}' \\ $$
Answered by mr W last updated on 28/Mar/20
y′=2±(√(4−2x+y))  let u=4−2x+y  (du/dx)=−2+(dy/dx)  2+(du/dx)=2±(√u)  (du/dx)=±(√u)  ∫(du/( (√u)))=±∫dx  2(√u)=±x+C  ⇒2(√(4−2x+y))±x=C  ⇒y=(((C±x)^2 )/4)+2x−4
$${y}'=\mathrm{2}\pm\sqrt{\mathrm{4}−\mathrm{2}{x}+{y}} \\ $$$${let}\:{u}=\mathrm{4}−\mathrm{2}{x}+{y} \\ $$$$\frac{{du}}{{dx}}=−\mathrm{2}+\frac{{dy}}{{dx}} \\ $$$$\mathrm{2}+\frac{{du}}{{dx}}=\mathrm{2}\pm\sqrt{{u}} \\ $$$$\frac{{du}}{{dx}}=\pm\sqrt{{u}} \\ $$$$\int\frac{{du}}{\:\sqrt{{u}}}=\pm\int{dx} \\ $$$$\mathrm{2}\sqrt{{u}}=\pm{x}+{C} \\ $$$$\Rightarrow\mathrm{2}\sqrt{\mathrm{4}−\mathrm{2}{x}+{y}}\pm{x}={C} \\ $$$$\Rightarrow{y}=\frac{\left({C}\pm{x}\right)^{\mathrm{2}} }{\mathrm{4}}+\mathrm{2}{x}−\mathrm{4} \\ $$

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