6.4.23 7.4

6.4.23.1 [1155] Problem 1
6.4.23.2 [1156] Problem 2
6.4.23.3 [1157] Problem 3
6.4.23.4 [1158] Problem 4
6.4.23.5 [1159] Problem 5

6.4.23.1 [1155] Problem 1

problem number 1155

Added March 9, 2019.

Problem Chapter 4.7.4.1, from Handbook of first order partial differential equations by Polyanin, Zaitsev, Moussiaux.

Solve for \(w(x,y)\)

\[ a w_x + b w_y = \left ( c \arccot (\frac {x}{\lambda } + k \arccot (\frac {y}{\beta } ) \right ) w \]

Mathematica

ClearAll["Global`*"]; 
pde =  a*D[w[x, y], x] + b*D[w[x, y], y] == (c*ArcCot[x/lambda] + k*ArcCot[y/beta])*w[x, y]; 
sol =  AbsoluteTiming[TimeConstrained[DSolve[pde, w[x, y], {x, y}], 60*10]];
 

\[\left \{\left \{w(x,y)\to \left (\lambda ^2+x^2\right )^{\frac {c \lambda }{2 a}} c_1\left (y-\frac {b x}{a}\right ) \exp \left (\frac {k \left (a \beta \log \left (a^2 \left (\beta ^2+y^2\right )\right )+2 \tan ^{-1}\left (\frac {y}{\beta }\right ) (b x-a y)+2 b x \cot ^{-1}\left (\frac {y}{\beta }\right )\right )+2 b c x \cot ^{-1}\left (\frac {x}{\lambda }\right )}{2 a b}\right )\right \}\right \}\]

Maple

restart; 
pde :=  a*diff(w(x,y),x)+ b*diff(w(x,y),y) = (c*arccot(x/lambda)+k*arccot(y/beta))*w(x,y); 
cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
 

\[w \left ( x,y \right ) ={\it \_F1} \left ( {\frac {ay-xb}{a}} \right ) \left ( {\frac {{x}^{2}}{{\lambda }^{2}}}+1 \right ) ^{{\frac {\lambda \,c}{2\,a}}} \left ( {\frac {{\beta }^{2}+{y}^{2}}{{\beta }^{2}}} \right ) ^{{\frac {k\beta }{2\,b}}}{{\rm e}^{{\frac {1}{2\,ba} \left ( -2\,a\arctan \left ( {\frac {y}{\beta }} \right ) ky-2\,b \left ( c\arctan \left ( {\frac {x}{\lambda }} \right ) -1/2\,\pi \, \left ( c+k \right ) \right ) x \right ) }}}\]

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6.4.23.2 [1156] Problem 2

problem number 1156

Added March 9, 2019.

Problem Chapter 4.7.4.2, from Handbook of first order partial differential equations by Polyanin, Zaitsev, Moussiaux.

Solve for \(w(x,y)\)

\[ a w_x + b w_y = c \arccot (\lambda x+\beta y) w \]

Mathematica

ClearAll["Global`*"]; 
pde =  a*D[w[x, y], x] + b*D[w[x, y], y] == c*ArcCot[lambda*x + beta*y]*w[x, y]; 
sol =  AbsoluteTiming[TimeConstrained[DSolve[pde, w[x, y], {x, y}], 60*10]];
 

\[\left \{\left \{w(x,y)\to c_1\left (y-\frac {b x}{a}\right ) \exp \left (\frac {c \left (a \log \left (a^2 \left (\beta ^2 y^2+2 \beta \lambda x y+\lambda ^2 x^2+1\right )\right )+2 \beta (b x-a y) \tan ^{-1}(\beta y+\lambda x)+2 x (a \lambda +b \beta ) \cot ^{-1}(\beta y+\lambda x)\right )}{2 a (a \lambda +b \beta )}\right )\right \}\right \}\]

Maple

restart; 
pde :=  a*diff(w(x,y),x)+ b*diff(w(x,y),y) = c*arccot(lambda*x+beta*y)*w(x,y); 
cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
 

\[w \left ( x,y \right ) ={\it \_F1} \left ( {\frac {ay-xb}{a}} \right ) \left ( {\beta }^{2}{y}^{2}+2\,\beta \,\lambda \,xy+{x}^{2}{\lambda }^{2}+1 \right ) ^{{\frac {c}{2\,a\lambda +2\,\beta \,b}}}{{\rm e}^{{\frac { \left ( -2\,a \left ( \beta \,y+x\lambda \right ) \arctan \left ( \beta \,y+x\lambda \right ) +x\pi \, \left ( a\lambda +\beta \,b \right ) \right ) c}{ \left ( 2\,a\lambda +2\,\beta \,b \right ) a}}}}\]

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6.4.23.3 [1157] Problem 3

problem number 1157

Added March 9, 2019.

Problem Chapter 4.7.4.3, from Handbook of first order partial differential equations by Polyanin, Zaitsev, Moussiaux.

Solve for \(w(x,y)\)

\[ a w_x + b w_y = a x \arccot (\lambda x+\beta y) w \]

Mathematica

ClearAll["Global`*"]; 
pde =  a*D[w[x, y], x] + b*D[w[x, y], y] == a*x*ArcCot[lambda*x + beta*y]*w[x, y]; 
sol =  AbsoluteTiming[TimeConstrained[DSolve[pde, w[x, y], {x, y}], 60*10]];
 

\[\left \{\left \{w(x,y)\to c_1\left (y-\frac {b x}{a}\right ) \exp \left (\frac {1}{4} \left (2 x^2 \cot ^{-1}(\beta y+\lambda x)+\frac {i (i a \beta y+a-i b \beta x)^2 \log (-a (\beta y+\lambda x-i))+i (b \beta x-a (\beta y+i))^2 \log (a (\beta y+\lambda x+i))+2 a x (a \lambda +b \beta )}{(a \lambda +b \beta )^2}\right )\right )\right \}\right \}\]

Maple

restart; 
pde :=  a*diff(w(x,y),x)+ b*diff(w(x,y),y) = a*x*arccot(lambda*x+beta*y)*w(x,y); 
cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
 

\[w \left ( x,y \right ) ={\it \_F1} \left ( {\frac {ay-xb}{a}} \right ) \left ( {\beta }^{2}{y}^{2}+2\,\beta \,\lambda \,xy+{x}^{2}{\lambda }^{2}+1 \right ) ^{-{\frac {\beta \, \left ( ay-xb \right ) a}{2\, \left ( a\lambda +\beta \,b \right ) ^{2}}}}{{\rm e}^{{\frac {-2\, \left ( \left ( -{\beta }^{2}{y}^{2}+{x}^{2}{\lambda }^{2}+1 \right ) a+2\,b\beta \,x \left ( \beta \,y+x\lambda \right ) \right ) a\arctan \left ( \beta \,y+x\lambda \right ) + \left ( \pi \,{x}^{2}{\lambda }^{2}+2\,\beta \,y+2\,x\lambda \right ) {a}^{2}+2\,\pi \,ab\beta \,\lambda \,{x}^{2}+\pi \,{b}^{2}{\beta }^{2}{x}^{2}}{4\, \left ( a\lambda +\beta \,b \right ) ^{2}}}}}\]

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6.4.23.4 [1158] Problem 4

problem number 1158

Added March 9, 2019.

Problem Chapter 4.7.4.4, from Handbook of first order partial differential equations by Polyanin, Zaitsev, Moussiaux.

Solve for \(w(x,y)\)

\[ a w_x + b \arccot ^n(\lambda x)w_y = \left ( c \arccot ^m(\mu x) + s \arccot ^k(\beta y) \right ) w \]

Mathematica

ClearAll["Global`*"]; 
pde =  a*D[w[x, y], x] + b*ArcCot[lambda*x]^n*D[w[x, y], y] == (c*ArcCot[mu*x]^m + s*ArcCot[beta*y]^k)*w[x, y]; 
sol =  AbsoluteTiming[TimeConstrained[DSolve[pde, w[x, y], {x, y}], 60*10]];
 

\[\left \{\left \{w(x,y)\to c_1\left (y-\int _1^x\frac {b \cot ^{-1}(\lambda K[1])^n}{a}dK[1]\right ) \exp \left (\int _1^x\frac {s \cot ^{-1}\left (\beta \left (y-\int _1^x\frac {b \cot ^{-1}(\lambda K[1])^n}{a}dK[1]+\int _1^{K[2]}\frac {b \cot ^{-1}(\lambda K[1])^n}{a}dK[1]\right )\right ){}^k+c \cot ^{-1}(\mu K[2])^m}{a}dK[2]\right )\right \}\right \}\]

Maple

restart; 
pde :=  a*diff(w(x,y),x)+ b*arccot(lambda*x)^n*diff(w(x,y),y) =(c*arccot(mu*x)^m+s*arccot(beta*y)^k)*w(x,y); 
cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
 

\[w \left ( x,y \right ) ={\it \_F1} \left ( -\int \!{\frac {b}{a} \left ( {\frac {\pi }{2}}-\arctan \left ( x\lambda \right ) \right ) ^{n}}\,{\rm d}x+y \right ) {{\rm e}^{\int ^{x}\!{\frac {1}{a} \left ( c \left ( {\frac {\pi }{2}}-\arctan \left ( \mu \,{\it \_b} \right ) \right ) ^{m}+s \left ( {\frac {\pi }{2}}-\arctan \left ( \beta \, \left ( \int \!{\frac {b}{a} \left ( {\frac {\pi }{2}}-\arctan \left ( {\it \_b}\,\lambda \right ) \right ) ^{n}}\,{\rm d}{\it \_b}-\int \!{\frac {b}{a} \left ( {\frac {\pi }{2}}-\arctan \left ( x\lambda \right ) \right ) ^{n}}\,{\rm d}x+y \right ) \right ) \right ) ^{k} \right ) }{d{\it \_b}}}}\]

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6.4.23.5 [1159] Problem 5

problem number 1159

Added March 9, 2019.

Problem Chapter 4.7.4.5, from Handbook of first order partial differential equations by Polyanin, Zaitsev, Moussiaux.

Solve for \(w(x,y)\)

\[ a w_x + b \arccot ^n(\lambda y)w_y = \left ( c \arccot ^m(\mu x) + s \arccot ^k(\beta y) \right ) w \]

Mathematica

ClearAll["Global`*"]; 
pde =  a*D[w[x, y], x] + b*ArcCot[lambda*y]^n*D[w[x, y], y] == (c*ArcCot[mu*x]^m + s*ArcCot[beta*y]^k)*w[x, y]; 
sol =  AbsoluteTiming[TimeConstrained[DSolve[pde, w[x, y], {x, y}], 60*10]];
 

\[\left \{\left \{w(x,y)\to c_1\left (\int _1^y\cot ^{-1}(\lambda K[1])^{-n}dK[1]-\frac {b x}{a}\right ) \exp \left (\int _1^y\frac {\cot ^{-1}(\lambda K[2])^{-n} \left (s \cot ^{-1}(\beta K[2])^k+c \cot ^{-1}\left (\frac {\mu \left (b x-a \int _1^y\cot ^{-1}(\lambda K[1])^{-n}dK[1]+a \int _1^{K[2]}\cot ^{-1}(\lambda K[1])^{-n}dK[1]\right )}{b}\right ){}^m\right )}{b}dK[2]\right )\right \}\right \}\]

Maple

restart; 
pde :=  a*diff(w(x,y),x)+ b*arccot(lambda*y)^n*diff(w(x,y),y) =(c*arccot(mu*x)^m+s*arccot(beta*y)^k)*w(x,y); 
cpu_time := timelimit(60*10,CodeTools[Usage](assign('sol',pdsolve(pde,w(x,y))),output='realtime'));
 

\[w \left ( x,y \right ) ={\it \_F1} \left ( -{\frac {a}{b}\int \! \left ( {\frac {\pi }{2}}-\arctan \left ( \lambda \,y \right ) \right ) ^{-n}\,{\rm d}y}+x \right ) {{\rm e}^{\int ^{y}\!{\frac { \left ( {\rm arccot} \left ({\it \_b}\,\lambda \right ) \right ) ^{-n}}{b} \left ( c \left ( {\frac {\pi }{2}}-\arctan \left ( \mu \, \left ( \int \!{\frac {a}{b} \left ( {\frac {\pi }{2}}-\arctan \left ( {\it \_b}\,\lambda \right ) \right ) ^{-n}}\,{\rm d}{\it \_b}-{\frac {a}{b}\int \! \left ( {\frac {\pi }{2}}-\arctan \left ( \lambda \,y \right ) \right ) ^{-n}\,{\rm d}y}+x \right ) \right ) \right ) ^{m}+s \left ( {\frac {\pi }{2}}-\arctan \left ( \beta \,{\it \_b} \right ) \right ) ^{k} \right ) }{d{\it \_b}}}}\]

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