Menu Close

Question-79966




Question Number 79966 by M±th+et£s last updated on 29/Jan/20
Commented by M±th+et£s last updated on 29/Jan/20
solve thd ODE
solvethdODE
Answered by mr W last updated on 29/Jan/20
(dx/dy)=((y^2 +y^2 e^(((x/y))^2 ) +2x^2 ((x/y))^2 )/(2xye^(((x/y))^2 ) ))  (dx/dy)=((1+e^(((x/y))^2 ) +2((x/y))^4 )/(2((x/y))e^(((x/y))^2 ) ))  let u=(x/y), i.e. x=uy  (dx/dy)=u+y(du/dy)  u+y(du/dy)=((1+e^u^2  +2u^4 )/(2ue^u^2  ))  y(du/dy)=((1+e^u^2  +2u^4 −2u^2 e^u^2  )/(2ue^u^2  ))  ((2ue^u^2  )/(1+e^u^2  +2u^4 −2u^2 e^u^2  ))du=(dy/y)  (e^u^2  /(1+e^u^2  +2u^4 −2u^2 e^u^2  ))du^2 =(dy/y)  let t=u^2   (e^t /(1+e^t +2t^2 −2te^t ))dt=(dy/y)  ∫(e^t /(1+e^t +2t^2 −2te^t ))dt=∫(dy/y)  ∫(e^t /(1+e^t +2t^2 −2te^t ))dt=ln (cy)  .....  not integrable ...
dxdy=y2+y2e(xy)2+2x2(xy)22xye(xy)2dxdy=1+e(xy)2+2(xy)42(xy)e(xy)2letu=xy,i.e.x=uydxdy=u+ydudyu+ydudy=1+eu2+2u42ueu2ydudy=1+eu2+2u42u2eu22ueu22ueu21+eu2+2u42u2eu2du=dyyeu21+eu2+2u42u2eu2du2=dyylett=u2et1+et+2t22tetdt=dyyet1+et+2t22tetdt=dyyet1+et+2t22tetdt=ln(cy)..notintegrable

Leave a Reply

Your email address will not be published. Required fields are marked *