Menu Close

Category: Differential Equation

f-x-f-x-dx-ln-sec-x-c-f-x-

Question Number 1597 by Rasheed Ahmad last updated on 25/Aug/15 $$\int\frac{{f}\left({x}\right)}{{f}\:'\left({x}\right)}{dx}={ln}\:{sec}\:{x}+{c} \\ $$$${f}\left({x}\right)=? \\ $$ Answered by 123456 last updated on 25/Aug/15 $$\int\frac{{y}}{{dy}/{dx}}{dx}=\mathrm{ln}\:\mathrm{sec}\:{x}+{c} \\ $$$$\frac{{d}}{{dx}}\left[\int\frac{{y}}{{dy}/{dx}}{dx}\right]=\frac{{d}}{{dx}}\left[\mathrm{ln}\:\mathrm{sec}\:{x}+{c}\right]…

Solve-the-following-D-E-dy-dx-2-2y-2-0-Does-d-2-y-dx-2-2-2y-2-0-have-any-solutions-other-than-y-1-

Question Number 1575 by 112358 last updated on 21/Aug/15 $${Solve}\:{the}\:{following}\:{D}.{E}. \\ $$$$\:\:\:\:\:\:\:\:\:\:\left(\frac{{dy}}{{dx}}\right)^{\mathrm{2}} +\mathrm{2}{y}+\mathrm{2}=\mathrm{0}\: \\ $$$${Does}\:\:\left(\frac{{d}^{\mathrm{2}} {y}}{{dx}^{\mathrm{2}} }\right)^{\mathrm{2}} +\mathrm{2}{y}+\mathrm{2}=\mathrm{0}\:{have} \\ $$$${any}\:{solutions}\:{other}\:{than} \\ $$$${y}=−\mathrm{1}\:? \\ $$ Commented…

Solve-differential-equations-1-x-3-1-y-xy-x-2-x-2-1-y-xy-2x-1-x-2-0-3-x-2-lnx-y-y-0-know-that-y-lnx-is-the-answer-

Question Number 132432 by Chhing last updated on 14/Feb/21 $$ \\ $$$$\:\:\mathrm{Solve}\:\:\mathrm{differential}\:\:\mathrm{equations} \\ $$$$\:\:\:\:\mathrm{1}/\:\left(\mathrm{x}^{\mathrm{3}} −\mathrm{1}\right)\mathrm{y}'+\mathrm{xy}=\mathrm{x} \\ $$$$\:\:\:\:\mathrm{2}/\:\left(\mathrm{x}^{\mathrm{2}} −\mathrm{1}\right)\mathrm{y}'−\mathrm{xy}+\frac{\mathrm{2x}}{\:\sqrt{\mathrm{1}+\mathrm{x}^{\mathrm{2}} }}=\mathrm{0} \\ $$$$\:\:\:\:\mathrm{3}/\:\mathrm{x}^{\mathrm{2}} \left(\mathrm{lnx}\right)\mathrm{y}''+\mathrm{y}=\mathrm{0}\:,\:\mathrm{know}\:\mathrm{that}\:\mathrm{y}=\mathrm{lnx}\:\mathrm{is}\:\mathrm{the}\:\mathrm{answer} \\ $$$$ \\…

Solve-the-following-DE-y-dy-dx-6x-5y-0-x-0-y-0-

Question Number 1352 by 112358 last updated on 24/Jul/15 $${Solve}\:{the}\:{following}\:{DE}\:: \\ $$$${y}\frac{{dy}}{{dx}}+\mathrm{6}{x}+\mathrm{5}{y}=\mathrm{0}\:\:\:\:\:\left({x}\neq\mathrm{0},{y}\neq\mathrm{0}\right) \\ $$ Answered by imhunter last updated on 27/Jul/15 $${q}.{no}.\mathrm{1352}\:\:\:\:\:\:\:\:\:\:\:{y}\:{dy}/{dx}=−\mathrm{6}{x}−\mathrm{5}{y} \\ $$$$ \\…

find-general-solution-y-64x-y-2-

Question Number 132398 by bramlexs22 last updated on 14/Feb/21 $$\mathrm{find}\:\mathrm{general}\:\mathrm{solution}\:\:\mathrm{y}'\:=\:\left(\mathrm{64x}+\mathrm{y}\right)^{\mathrm{2}} \: \\ $$ Answered by EDWIN88 last updated on 14/Feb/21 $$\mathrm{let}\:\mathrm{v}\:=\:\mathrm{64x}+\mathrm{y}\:\Leftrightarrow\frac{\mathrm{dv}}{\mathrm{dx}}\:=\:\mathrm{64}+\frac{\mathrm{dy}}{\mathrm{dx}} \\ $$$$\mathrm{or}\:\frac{\mathrm{dy}}{\mathrm{dx}}\:=\:\frac{\mathrm{dv}}{\mathrm{dx}}−\mathrm{64}\: \\ $$$$\:\Leftrightarrow\:\frac{\mathrm{dv}}{\mathrm{dx}}\:\:−\:\mathrm{64}\:=\:\mathrm{v}^{\mathrm{2}}…