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Category: Differential Equation

x-sin-y-x-y-cos-y-x-dx-x-cos-y-x-dy-0-

Question Number 155965 by john_santu last updated on 06/Oct/21 $$\left({x}\:\mathrm{sin}\:\frac{{y}}{{x}}−{y}\:\mathrm{cos}\:\frac{{y}}{{x}}\right){dx}+{x}\:\mathrm{cos}\:\frac{{y}}{{x}}\:{dy}=\mathrm{0} \\ $$ Answered by mindispower last updated on 07/Oct/21 $$\left({tg}\left(\frac{{y}}{{x}}\right)−\frac{{y}}{{x}}\right){dx}+{dy}=\mathrm{0} \\ $$$$\frac{{y}}{{x}}={u} \\ $$$${dy}={xdu}+{udx} \\…

3x-2-9xy-5y-2-dx-6x-2-4xy-dy-

Question Number 90394 by jagoll last updated on 23/Apr/20 $$\left(\mathrm{3x}^{\mathrm{2}} +\mathrm{9xy}+\mathrm{5y}^{\mathrm{2}} \right)\mathrm{dx}\:=\:\left(\mathrm{6x}^{\mathrm{2}} +\mathrm{4xy}\right)\mathrm{dy} \\ $$ Commented by john santu last updated on 23/Apr/20 $$\left(\mathrm{3}+\mathrm{9}\left(\frac{{y}}{{x}}\right)+\mathrm{5}\left(\frac{{y}}{{x}}\right)^{\mathrm{2}} \right)\:=\:\left(\mathrm{6}+\mathrm{4}\left(\frac{{y}}{{x}}\right)\right)\:{dy}…

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

Question Number 90262 by jagoll last updated on 22/Apr/20 $$\left(\mathrm{y}+\sqrt{\mathrm{x}^{\mathrm{2}} +\mathrm{y}^{\mathrm{2}} }\right)\:\mathrm{dx}\:=\:\mathrm{x}\:\mathrm{dy}\: \\ $$ Commented by john santu last updated on 22/Apr/20 $$\left(\frac{{y}}{{x}}+\sqrt{\mathrm{1}+\left(\frac{{y}}{{x}}\right)^{\mathrm{2}} }\right)\:{dx}\:=\:{dy}\: \\…

x-dy-dx-y-cos-2y-x-3x-4-

Question Number 89978 by jagoll last updated on 20/Apr/20 $$\left(\mathrm{x}\:\frac{\mathrm{dy}}{\mathrm{dx}}−\mathrm{y}\right)\left(\mathrm{cos}\:\left(\frac{\mathrm{2y}}{\mathrm{x}}\right)\right)\:=\:−\mathrm{3x}^{\mathrm{4}} \\ $$ Commented by john santu last updated on 20/Apr/20 $$\left[\:{let}\:{y}\:=\:{ux}\:\right]\:\Rightarrow\frac{{dy}}{{dx}}\:=\:{u}\:+\:{x}\frac{{du}}{{dx}} \\ $$$$\left\{{ux}\:+{x}^{\mathrm{2}} \:\frac{{du}}{{dx}}\:−{ux}\:\right\}\left(\mathrm{cos}\:\mathrm{2}{u}\right)\:=\:−\mathrm{3}{x}^{\mathrm{4}} \\…