6.1.4 problem number 4

problem number 420

Added January 2, 2019.

Problem 1.4 from Handbook of first order partial differential equations by Polyanin, Zaitsev, Moussiaux.

Solve for \(w(x,y)\) \[ w_y = w f(x,y) \]

Mathematica

ClearAll["Global`*"]; 
pde =  D[w[x, y], y] == w[x, y]*f[x, y]; 
sol =  AbsoluteTiming[TimeConstrained[DSolve[pde, w[x, y], {x, y}], 60*10]];
 

\[\left \{\left \{w(x,y)\to c_1(x) \exp \left (\int _1^yf(x,K[1])dK[1]\right )\right \}\right \}\]

Maple

restart; 
pde := diff(w(x,y),x)=w(x,y)*f(x,y); 
cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
 

\[w \left ( x,y \right ) ={\it \_F1} \left ( y \right ) {{\rm e}^{\int \!f \left ( x,y \right ) \,{\rm d}x}}\]

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