2.21.1.24 First order ODE’s not exact but made exact with integrating factor found by inspection

These are ode’s of the form \(M dx + N dy=0\) where it become exact using integrating factor \(\mu \) to obtain \(\mu M dx + \mu N dy=0\). The integrating factor is found by inspection (trials over selected candidates). This is tried only when the three known methods to find integrating factor fail. Number of problems in this table is 105

Column notations: A is ODE degree. B is Program Number of solutions generated. C is CAS Number of solutions generated.

Table 2.562: exactByInspection

#

ODE

A

B

C

CAS classification

Solved?

Verified?

time (sec)

82

\[ {}\left (x -y\right ) y^{\prime } = x +y \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.955

83

\[ {}x \left (x +y\right ) y^{\prime } = y \left (x -y\right ) \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.985

87

\[ {}x^{2} y^{\prime } = x y+y^{2} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.517

123

\[ {}x y+y^{2}-x^{2} y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.591

131

\[ {}x^{2} y^{\prime } = x y+3 y^{2} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.075

596

\[ {}y^{\prime } = \frac {x +y}{x -y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.519

999

\[ {}y^{\prime } = \frac {x y+y^{2}}{x^{2}} \]

i.c.

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.893

1005

\[ {}y^{\prime } = \frac {x +y}{x -y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.582

1008

\[ {}y^{\prime } = \frac {2 y+x}{y+2 x} \]

1

1

3

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

3.706

1683

\[ {}y^{\prime } = \frac {t +y}{t -y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

2.089

1901

\[ {}\left (x +y\right ) y^{\prime }+x = y \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

2.139

1908

\[ {}\left (x y-x^{2}\right ) y^{\prime }-y^{2} = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

2.395

1917

\[ {}y^{\prime } = \frac {x +y}{x -y} \]

i.c.

1

0

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

3.561

1919

\[ {}\left (3 x y-2 x^{2}\right ) y^{\prime } = 2 y^{2}-x y \]

i.c.

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

6.517

1978

\[ {}\left (x^{2}+y^{2}+x \right ) y^{\prime } = y \]

1

1

1

[_rational]

2.014

2018

\[ {}x^{2} y^{\prime }+y^{2} = x y \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.638

2035

\[ {}2 x +y-\left (x -2 y\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

2.431

2070

\[ {}x y-y^{2}-x^{2} y^{\prime } = 0 \]

i.c.

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

2.412

2579

\[ {}x y^{\prime }+y \ln \left (x \right ) = y \ln \left (y\right ) \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

2.011

2584

\[ {}2 x \left (y+2 x \right ) y^{\prime } = y \left (4 x -y\right ) \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.148

3105

\[ {}x y^{\prime } = x^{5}+x^{3} y^{2}+y \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.711

3106

\[ {}\left (x +y\right ) y^{\prime } = y-x \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.237

3120

\[ {}\left (x y-x^{2}\right ) y^{\prime } = y^{2} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.762

3156

\[ {}x y^{\prime } = y \left (1+\ln \left (y\right )-\ln \left (x \right )\right ) \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

3.218

3185

\[ {}x^{2}+y+y^{2}-x y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.753

3420

\[ {}x y^{\prime } = x^{2}+y \left (y+1\right ) \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.05

3442

\[ {}x y^{\prime } = y+\left (x^{2}-y^{2}\right ) f \left (x \right ) \]

1

1

1

[[_homogeneous, ‘class D‘], _Riccati]

1.607

3473

\[ {}x y^{\prime }+\left (1-\ln \left (x \right )-\ln \left (y\right )\right ) y = 0 \]

1

1

1

[[_homogeneous, ‘class G‘]]

1.304

3516

\[ {}x^{2} y^{\prime } = \left (a y+x \right ) y \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

0.651

3690

\[ {}\left (x +y\right ) y^{\prime }+x -y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

0.908

3700

\[ {}\left (y+2 x \right ) y^{\prime }+x -2 y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

0.872

3717

\[ {}\left (2 y+x \right ) y^{\prime }+2 x -y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

0.891

3737

\[ {}\left (x +4 y\right ) y^{\prime }+4 x -y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

0.891

3756

\[ {}\left (x a +b y\right ) y^{\prime } = b x +a y \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

2.796

3779

\[ {}x \left (x -y\right ) y^{\prime }+y^{2} = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

0.925

3856

\[ {}\left (x^{2}+y^{2}+x \right ) y^{\prime } = y \]

1

1

1

[_rational]

0.873

3906

\[ {}x \left (x +6 y^{2}\right ) y^{\prime }+x y-3 y^{3} = 0 \]

1

1

1

[[_homogeneous, ‘class G‘], _rational]

1.339

3907

\[ {}x \left (x^{2}-6 y^{2}\right ) y^{\prime } = 4 \left (x^{2}+3 y^{2}\right ) y \]

1

1

2

[[_homogeneous, ‘class A‘], _rational, _dAlembert]

3.709

3913

\[ {}x \left (1+x y^{2}\right ) y^{\prime } = \left (2-3 x y^{2}\right ) y \]

1

1

2

[[_homogeneous, ‘class G‘], _rational]

3.484

3926

\[ {}\left (x \,a^{2}+\left (x^{2}-y^{2}\right ) y\right ) y^{\prime }+x \left (x^{2}-y^{2}\right ) = y a^{2} \]

1

1

0

[_rational]

1.569

3938

\[ {}x \left (x -y^{3}\right ) y^{\prime } = \left (3 x +y^{3}\right ) y \]

1

1

3

[[_homogeneous, ‘class G‘], _rational]

3.442

3944

\[ {}x \left (x +y+2 y^{3}\right ) y^{\prime } = y \left (x -y\right ) \]

1

1

1

[_rational]

1.237

3984

\[ {}x \left (x -y \tan \left (\frac {y}{x}\right )\right ) y^{\prime }+\left (x +y \tan \left (\frac {y}{x}\right )\right ) y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

1.917

4429

\[ {}x +y-\left (x -y\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.359

4434

\[ {}y+x \ln \left (\frac {y}{x}\right ) y^{\prime }-2 x y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

3.474

4440

\[ {}x y-y^{2}-x^{2} y^{\prime } = 0 \]

i.c.

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.472

4481

\[ {}x^{2}-y^{2}-y-\left (x^{2}-y^{2}-x \right ) y^{\prime } = 0 \]

1

1

1

[[_1st_order, _with_linear_symmetries], _rational]

2.471

4492

\[ {}y-\left (x^{2}+y^{2}+x \right ) y^{\prime } = 0 \]

1

1

1

[_rational]

1.223

4569

\[ {}\left (2 x y^{3}+x y+x^{2}\right ) y^{\prime }-x y+y^{2} = 0 \]

1

1

1

[_rational]

1.994

4781

\[ {}x^{2} y^{\prime }+y^{2}-x y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.135

4784

\[ {}y^{2}-x y+\left (x^{2}+x y\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.007

4789

\[ {}y^{\prime } = \frac {2 y^{2}}{x}+\frac {y}{x}-2 x \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.372

5121

\[ {}x^{2} y^{\prime } = y^{2}-x y y^{\prime } \]

i.c.

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

5.341

5124

\[ {}x^{2} y^{\prime }+y^{2} = x y y^{\prime } \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.405

5243

\[ {}y \sqrt {x^{2}+y^{2}}-x \left (x +\sqrt {x^{2}+y^{2}}\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class G‘], _dAlembert]

4.592

5272

\[ {}y \left (x -2 y\right )-x^{2} y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.345

5841

\[ {}x^{2} y^{\prime }+y^{2}-x y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

0.875

5842

\[ {}x +y-\left (x -y\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.274

5894

\[ {}-y+x y^{\prime } = x^{2}+y^{2} \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.256

5896

\[ {}x +y y^{\prime }+y-x y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.022

6112

\[ {}x y^{\prime } = y+x^{2}+y^{2} \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.287

6116

\[ {}y^{\prime } = \frac {y^{2}}{x y-x^{2}} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.466

6254

\[ {}y^{\prime } = \frac {2 y+x}{2 x -y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

3.238

6261

\[ {}y^{\prime } = \frac {x +y}{x -y} \]

i.c.

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

6.302

7066

\[ {}x^{2} y^{\prime }+y^{2} = x y y^{\prime } \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.532

8473

\[ {}x^{2} y^{\prime }-y^{2}-x y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.117

8611

\[ {}\left (x^{2}+y^{2}+x \right ) y^{\prime }-y = 0 \]

1

1

1

[_rational]

1.581

8637

\[ {}\left (6 x y^{2}+x^{2}\right ) y^{\prime }-y \left (3 y^{2}-x \right ) = 0 \]

1

1

1

[[_homogeneous, ‘class G‘], _rational]

1.961

8653

\[ {}\left (2 x y^{3}+x y+x^{2}\right ) y^{\prime }-x y+y^{2} = 0 \]

1

1

1

[_rational]

1.961

8701

\[ {}\left (y f \left (x^{2}+y^{2}\right )-x \right ) y^{\prime }+y+x f \left (x^{2}+y^{2}\right ) = 0 \]

1

1

1

[[_1st_order, _with_linear_symmetries]]

9.193

9021

\[ {}y^{\prime } = \frac {y-\ln \left (\frac {1+x}{-1+x}\right ) x^{3}+\ln \left (\frac {1+x}{-1+x}\right ) x y^{2}}{x} \]

1

1

1

[[_homogeneous, ‘class D‘], _Riccati]

2.185

9022

\[ {}y^{\prime } = \frac {y+{\mathrm e}^{\frac {1+x}{-1+x}} x^{3}+{\mathrm e}^{\frac {1+x}{-1+x}} x y^{2}}{x} \]

1

1

1

[[_homogeneous, ‘class D‘], _Riccati]

3.069

9062

\[ {}y^{\prime } = \frac {\left (x^{3}+3 y^{2}\right ) y}{\left (x +6 y^{2}\right ) x} \]

1

1

1

[_rational, [_1st_order, ‘_with_symmetry_[F(x),G(x)*y+H(x)]‘]]

1.286

9063

\[ {}y^{\prime } = \frac {y \left (x -y\right )}{x \left (x -y^{3}\right )} \]

1

1

3

[_rational]

0.972

9082

\[ {}y^{\prime } = \frac {y \left (x +y\right )}{x \left (x +y^{3}\right )} \]

1

1

3

[_rational]

1.083

9084

\[ {}y^{\prime } = \frac {\left (x^{2}+3 y^{2}\right ) y}{\left (x +6 y^{2}\right ) x} \]

1

1

1

[_rational, [_1st_order, ‘_with_symmetry_[F(x),G(x)*y+H(x)]‘]]

1.331

9115

\[ {}y^{\prime } = \frac {\left (x^{4}+x^{3}+x +3 y^{2}\right ) y}{\left (x +6 y^{2}\right ) x} \]

1

1

1

[_rational, [_1st_order, ‘_with_symmetry_[F(x),G(x)*y+H(x)]‘]]

1.605

9157

\[ {}y^{\prime } = \frac {y \left (x +y\right )}{x \left (x +y+y^{3}+y^{4}\right )} \]

1

1

1

[_rational]

2.342

9164

\[ {}y^{\prime } = \frac {y \left (x -y\right )}{x \left (x -y-y^{3}-y^{4}\right )} \]

1

1

1

[_rational]

2.397

9205

\[ {}y^{\prime } = \frac {-30 x^{3} y+12 x^{6}+70 x^{\frac {7}{2}}-30 x^{3}-25 y \sqrt {x}+50 x -25 \sqrt {x}-25}{5 \left (-5 y+2 x^{3}+10 \sqrt {x}-5\right ) x} \]

1

1

2

[_rational, [_1st_order, ‘_with_symmetry_[F(x),G(x)]‘], [_Abel, ‘2nd type‘, ‘class B‘]]

5.822

9244

\[ {}y^{\prime } = -\left (-\frac {\ln \left (y\right )}{x}+\frac {\cos \left (x \right ) \ln \left (y\right )}{\sin \left (x \right )}-\textit {\_F1} \left (x \right )\right ) y \]

1

1

1

[[_1st_order, ‘_with_symmetry_[F(x),G(x)*y+H(x)]‘]]

9.809

9254

\[ {}y^{\prime } = -\left (-\frac {\ln \left (y\right )}{x}+\frac {\ln \left (y\right )}{x \ln \left (x \right )}-\textit {\_F1} \left (x \right )\right ) y \]

1

1

1

[[_1st_order, ‘_with_symmetry_[F(x),G(x)*y+H(x)]‘]]

3.809

9257

\[ {}y^{\prime } = -\frac {\left (-\frac {\ln \left (y\right )^{2}}{2 x}-\textit {\_F1} \left (x \right )\right ) y}{\ln \left (y\right )} \]

1

1

2

[NONE]

3.614

11132

\[ {}x^{2} y^{\prime }+y^{2}-x y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

0.946

11155

\[ {}x^{2} y^{\prime }+y^{2}-x y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

0.939

11157

\[ {}x +y-\left (x -y\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.5

11160

\[ {}-y+x y^{\prime } = x^{2}+y^{2} \]

1

1

1

[[_homogeneous, ‘class D‘], _rational, _Riccati]

1.434

11168

\[ {}x +y y^{\prime }+y-x y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.106

11183

\[ {}x y^{2} \left (3 y+x y^{\prime }\right )-2 y+x y^{\prime } = 0 \]

1

1

2

[[_homogeneous, ‘class G‘], _rational]

3.125

11612

\[ {}y+x \left (x^{2}+y^{2}\right )^{2}+\left (y \left (x^{2}+y^{2}\right )^{2}-x \right ) y^{\prime } = 0 \]

1

1

1

[[_1st_order, _with_linear_symmetries], _rational]

1.89

12120

\[ {}x \left (\ln \left (x \right )-\ln \left (y\right )\right ) y^{\prime }-y = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

5.086

12140

\[ {}y \left (x -y\right )-x^{2} y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.256

12152

\[ {}y \left (x -y\right )-x^{2} y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.2

12440

\[ {}x +y+\left (y-x \right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.426

13379

\[ {}x^{2} y^{\prime }-x y = y^{2} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

0.936

13384

\[ {}y^{\prime }-\frac {3 y}{x} = \frac {y^{2}}{x^{2}} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.058

13445

\[ {}y^{\prime } = \frac {2 y+x}{2 x -y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.306

14350

\[ {}y^{\prime }-\frac {y}{t} = \frac {y^{2}}{t^{2}} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, _Bernoulli]

1.177

14364

\[ {}y^{\prime } = \frac {4 y+t}{4 t +y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

3.911

14369

\[ {}y^{2} = \left (t y-4 t^{2}\right ) y^{\prime } \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class B‘]]

1.947

14374

\[ {}t \left (\ln \left (t \right )-\ln \left (y\right )\right ) y^{\prime } = y \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

3.945

14958

\[ {}y^{\prime } = \frac {x +y}{x -y} \]

1

1

1

[[_homogeneous, ‘class A‘], _rational, [_Abel, ‘2nd type‘, ‘class A‘]]

1.728

15008

\[ {}x y^{\prime } = y \left (\ln \left (y\right )-\ln \left (x \right )\right ) \]

1

1

1

[[_homogeneous, ‘class A‘], _dAlembert]

6.031

15022

\[ {}2 x y^{\prime } \left (x -y^{2}\right )+y^{3} = 0 \]

1

1

1

[[_homogeneous, ‘class G‘], _rational]

2.533

15171

\[ {}y^{3}+2 \left (x^{2}-x y^{2}\right ) y^{\prime } = 0 \]

1

1

1

[[_homogeneous, ‘class G‘], _rational]

1.227