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Category: Differential Equation

If-x-amp-y-satisfy-the-equation-x-2-y-2-4x-6y-1-0-find-minimum-value-of-x-y-

Question Number 97266 by bobhans last updated on 07/Jun/20 $$\mathrm{If}\:\mathrm{x}\:\&\mathrm{y}\:\mathrm{satisfy}\:\mathrm{the}\:\mathrm{equation}\:\mathrm{x}^{\mathrm{2}} +\mathrm{y}^{\mathrm{2}} −\mathrm{4x}−\mathrm{6y}−\mathrm{1}\:=\mathrm{0} \\ $$$$\mathrm{find}\:\mathrm{minimum}\:\mathrm{value}\:\mathrm{of}\:\mathrm{x}+\mathrm{y}\:? \\ $$ Commented by bobhans last updated on 07/Jun/20 $$\mathrm{f}\left(\mathrm{x},\mathrm{y},\lambda\right)\:=\:\mathrm{x}+\mathrm{y}+\lambda\left(\mathrm{x}^{\mathrm{2}} +\mathrm{y}^{\mathrm{2}}…

solve-1-x-2-dy-dx-xy-xy-2-

Question Number 97001 by bemath last updated on 06/Jun/20 $$\mathrm{solve}\:\left(\mathrm{1}+\mathrm{x}^{\mathrm{2}} \right)\:\frac{\mathrm{dy}}{\mathrm{dx}}\:=\:\mathrm{xy}−\mathrm{xy}^{\mathrm{2}} \\ $$ Commented by bobhans last updated on 06/Jun/20 $$\frac{\mathrm{dy}}{\mathrm{dx}}\:=\:\frac{\mathrm{x}\left(\mathrm{y}−\mathrm{y}^{\mathrm{2}} \right)}{\mathrm{x}^{\mathrm{2}} +\mathrm{1}}\:\Leftrightarrow\:\frac{\mathrm{dy}}{\mathrm{y}−\mathrm{y}^{\mathrm{2}} }\:=\:\frac{\mathrm{x}\:\mathrm{dx}}{\mathrm{x}^{\mathrm{2}} +\mathrm{1}}…

solve-dy-dx-x-y-4-x-y-6-

Question Number 96610 by bemath last updated on 03/Jun/20 $$\mathrm{solve}\:\frac{\mathrm{dy}}{\mathrm{dx}}\:=\:\frac{\mathrm{x}+\mathrm{y}+\mathrm{4}}{\mathrm{x}−\mathrm{y}−\mathrm{6}} \\ $$ Commented by bobhans last updated on 03/Jun/20 $$\mathrm{set}\:\mathrm{x}+\mathrm{y}+\mathrm{4}\:=\:\mathrm{0}\:\&\:\mathrm{x}−\mathrm{y}−\mathrm{6}=\mathrm{0}\:,\:\mathrm{intercept} \\ $$$$\mathrm{at}\:\mathrm{point}\left(\mathrm{1},−\mathrm{5}\right).\:\mathrm{Let}\:\mathrm{x}=\mathrm{X}+\mathrm{1}\:,\:\mathrm{y}=\mathrm{Y}−\mathrm{5} \\ $$$$\mathrm{dX}=\mathrm{dx}\:,\:\mathrm{dY}=\mathrm{dy}.\:\mathrm{Let}\:\mathrm{Y}=\mathrm{XZ} \\…

x-x-1-dy-dx-2x-1-y-0-

Question Number 96596 by bemath last updated on 03/Jun/20 $${x}\left({x}+\mathrm{1}\right)\:\frac{{dy}}{{dx}}−\left(\mathrm{2}{x}+\mathrm{1}\right){y}\:=\:\mathrm{0} \\ $$ Answered by bobhans last updated on 03/Jun/20 $$\frac{{dy}}{{dx}}\:=\:\frac{\mathrm{2}{x}+\mathrm{1}}{{x}^{\mathrm{2}} +{x}}.{y}\:\Rightarrow\frac{{dy}}{{y}}\:=\:\frac{\left(\mathrm{2}{x}+\mathrm{1}\right){dx}}{{x}^{\mathrm{2}} +{x}} \\ $$$$\mathrm{ln}\mid\mathrm{y}\mid\:=\:\mathrm{ln}\mid\mathrm{C}\left({x}^{\mathrm{2}} +{x}\right)\mid\:\Rightarrow\:\mathrm{y}=\:\mathrm{C}\left({x}^{\mathrm{2}}…

solve-dy-dx-4x-y-1-2-when-y-0-1-

Question Number 96392 by john santu last updated on 01/Jun/20 $$\mathrm{solve}\:\frac{\mathrm{dy}}{\mathrm{dx}}\:=\:\left(\mathrm{4x}+\mathrm{y}+\mathrm{1}\right)^{\mathrm{2}} \:,\:\mathrm{when}\: \\ $$$$\mathrm{y}\left(\mathrm{0}\right)\:=\:\mathrm{1} \\ $$ Answered by bobhans last updated on 01/Jun/20 $$\mathrm{set}\:\mathrm{s}\:=\:\mathrm{4x}+\mathrm{y}+\mathrm{1}\:\Rightarrow\:\frac{\mathrm{ds}}{\mathrm{dx}}\:=\:\mathrm{4}\:+\frac{\mathrm{dy}}{\mathrm{dx}} \\…

dy-dx-y-2-x-2-y-x-

Question Number 96217 by john santu last updated on 30/May/20 $$\frac{\mathrm{dy}}{\mathrm{dx}}\:=\:\left(\frac{\mathrm{y}^{\mathrm{2}} −\mathrm{x}^{\mathrm{2}} +\mathrm{y}}{\mathrm{x}}\right)\: \\ $$ Answered by bobhans last updated on 30/May/20 $$\mathrm{set}\:\mathrm{y}\:=\:{xz}\:\Rightarrow\:\frac{{dy}}{{dx}}\:=\:{z}\:+\:{x}\:\frac{{dz}}{{dx}} \\ $$$${z}\:+\:{x}\:\frac{{dz}}{{dx}}\:=\:\frac{{x}^{\mathrm{2}}…