Internal problem ID [9276]
Internal file name [OUTPUT/8212_Monday_June_06_2022_02_18_41_AM_13215771/index.tex]
Book: Differential Gleichungen, E. Kamke, 3rd ed. Chelsea Pub. NY, 1948
Section: Chapter 1, Additional non-linear first order
Problem number: 943.
ODE order: 1.
ODE degree: 1.
The type(s) of ODE detected by this program : "first_order_ode_lie_symmetry_calculated"
Maple gives the following as the ode type
[[_1st_order, _with_linear_symmetries], _rational, [_Abel, `2nd type`, `class C`]]
\[ \boxed {y^{\prime }-\frac {-128 x y-24 x^{3}+32 x^{2}-128 x +512 y^{3}+192 y^{2} x^{2}-384 y^{2} x +24 y x^{4}-96 x^{3} y+96 x^{2} y+x^{6}-6 x^{5}+12 x^{4}}{512 y+64 x^{2}-128 x +512}=0} \]
Writing the ode as \begin {align*} y^{\prime }&=\frac {x^{6}-6 x^{5}+24 y \,x^{4}+12 x^{4}-96 x^{3} y +192 x^{2} y^{2}-24 x^{3}+96 x^{2} y -384 x \,y^{2}+512 y^{3}+32 x^{2}-128 x y -128 x}{64 x^{2}-128 x +512 y +512}\\ y^{\prime }&= \omega \left ( x,y\right ) \end {align*}
The condition of Lie symmetry is the linearized PDE given by \begin {align*} \eta _{x}+\omega \left ( \eta _{y}-\xi _{x}\right ) -\omega ^{2}\xi _{y}-\omega _{x}\xi -\omega _{y}\eta =0\tag {A} \end {align*}
The type of this ode is not in the lookup table. To determine \(\xi ,\eta \) then (A) is solved using ansatz. Making bivariate polynomials of degree 1 to use as anstaz gives \begin{align*} \tag{1E} \xi &= x a_{2}+y a_{3}+a_{1} \\ \tag{2E} \eta &= x b_{2}+y b_{3}+b_{1} \\ \end{align*} Where the unknown coefficients are \[ \{a_{1}, a_{2}, a_{3}, b_{1}, b_{2}, b_{3}\} \] Substituting equations (1E,2E) and \(\omega \) into (A) gives \begin{equation} \tag{5E} b_{2}+\frac {\left (x^{6}-6 x^{5}+24 y \,x^{4}+12 x^{4}-96 x^{3} y +192 x^{2} y^{2}-24 x^{3}+96 x^{2} y -384 x \,y^{2}+512 y^{3}+32 x^{2}-128 x y -128 x \right ) \left (b_{3}-a_{2}\right )}{64 x^{2}-128 x +512 y +512}-\frac {\left (x^{6}-6 x^{5}+24 y \,x^{4}+12 x^{4}-96 x^{3} y +192 x^{2} y^{2}-24 x^{3}+96 x^{2} y -384 x \,y^{2}+512 y^{3}+32 x^{2}-128 x y -128 x \right )^{2} a_{3}}{4096 \left (x^{2}-2 x +8 y +8\right )^{2}}-\left (\frac {6 x^{5}-30 x^{4}+96 x^{3} y +48 x^{3}-288 x^{2} y +384 x \,y^{2}-72 x^{2}+192 x y -384 y^{2}+64 x -128 y -128}{64 x^{2}-128 x +512 y +512}-\frac {\left (x^{6}-6 x^{5}+24 y \,x^{4}+12 x^{4}-96 x^{3} y +192 x^{2} y^{2}-24 x^{3}+96 x^{2} y -384 x \,y^{2}+512 y^{3}+32 x^{2}-128 x y -128 x \right ) \left (-2+2 x \right )}{64 \left (x^{2}-2 x +8 y +8\right )^{2}}\right ) \left (x a_{2}+y a_{3}+a_{1}\right )-\left (\frac {24 x^{4}-96 x^{3}+384 x^{2} y +96 x^{2}-768 x y +1536 y^{2}-128 x}{64 x^{2}-128 x +512 y +512}-\frac {x^{6}-6 x^{5}+24 y \,x^{4}+12 x^{4}-96 x^{3} y +192 x^{2} y^{2}-24 x^{3}+96 x^{2} y -384 x \,y^{2}+512 y^{3}+32 x^{2}-128 x y -128 x}{8 \left (x^{2}-2 x +8 y +8\right )^{2}}\right ) \left (x b_{2}+y b_{3}+b_{1}\right ) = 0 \end{equation} Putting the above in normal form gives \[ -\frac {x^{12} a_{3}-12 x^{11} a_{3}+48 x^{10} y a_{3}+60 x^{10} a_{3}-480 x^{9} y a_{3}+960 x^{8} y^{2} a_{3}-192 x^{9} a_{3}+1920 x^{8} y a_{3}-7680 x^{7} y^{2} a_{3}+10240 x^{6} y^{3} a_{3}+320 x^{8} a_{2}+496 x^{8} a_{3}-64 x^{8} b_{3}-4608 x^{7} y a_{3}+23040 x^{6} y^{2} a_{3}-61440 x^{5} y^{3} a_{3}+61440 x^{4} y^{4} a_{3}+256 x^{7} a_{1}-2304 x^{7} a_{2}-1216 x^{7} a_{3}+1024 x^{7} b_{2}+512 x^{7} b_{3}+8192 x^{6} y a_{2}+8192 x^{6} y a_{3}-1024 x^{6} y b_{3}-36864 x^{5} y^{2} a_{3}+122880 x^{4} y^{3} a_{3}-245760 x^{3} y^{4} a_{3}+196608 x^{2} y^{5} a_{3}-1792 x^{6} a_{1}+9728 x^{6} a_{2}+2880 x^{6} a_{3}+1024 x^{6} b_{1}-6144 x^{6} b_{2}-2048 x^{6} b_{3}+6144 x^{5} y a_{1}-43008 x^{5} y a_{2}-12288 x^{5} y a_{3}+24576 x^{5} y b_{2}+6144 x^{5} y b_{3}+73728 x^{4} y^{2} a_{2}+33792 x^{4} y^{2} a_{3}-98304 x^{3} y^{3} a_{3}+245760 x^{2} y^{4} a_{3}-393216 x \,y^{5} a_{3}+262144 y^{6} a_{3}+7680 x^{5} a_{1}-27648 x^{5} a_{2}-4608 x^{5} a_{3}-6144 x^{5} b_{1}+24576 x^{5} b_{2}+6144 x^{5} b_{3}-30720 x^{4} y a_{1}+135168 x^{4} y a_{2}+15360 x^{4} y a_{3}+24576 x^{4} y b_{1}-98304 x^{4} y b_{2}-12288 x^{4} y b_{3}+49152 x^{3} y^{2} a_{1}-245760 x^{3} y^{2} a_{2}+196608 x^{3} y^{2} b_{2}+262144 x^{2} y^{3} a_{2}-16384 x^{2} y^{3} a_{3}+65536 x^{2} y^{3} b_{3}-21504 x^{4} a_{1}+41984 x^{4} a_{2}+7168 x^{4} a_{3}+24576 x^{4} b_{1}-61440 x^{4} b_{2}-11264 x^{4} b_{3}+98304 x^{3} y a_{1}-270336 x^{3} y a_{2}-2048 x^{3} y a_{3}-98304 x^{3} y b_{1}+294912 x^{3} y b_{2}+24576 x^{3} y b_{3}-147456 x^{2} y^{2} a_{1}+491520 x^{2} y^{2} a_{2}-73728 x^{2} y^{2} a_{3}+196608 x^{2} y^{2} b_{1}-393216 x^{2} y^{2} b_{2}+98304 x^{2} y^{2} b_{3}+131072 x \,y^{3} a_{1}-393216 x \,y^{3} a_{2}+163840 x \,y^{3} a_{3}+524288 x \,y^{3} b_{2}-131072 x \,y^{3} b_{3}+262144 y^{4} a_{2}-131072 y^{4} a_{3}+262144 y^{4} b_{3}+30720 x^{3} a_{1}-57344 x^{3} a_{2}-8192 x^{3} a_{3}-57344 x^{3} b_{1}+65536 x^{3} b_{2}+24576 x^{3} b_{3}-188416 x^{2} y a_{1}+212992 x^{2} y a_{2}+294912 x^{2} y b_{1}-458752 x^{2} y b_{2}-32768 x^{2} y b_{3}+294912 x \,y^{2} a_{1}-524288 x \,y^{2} a_{2}+131072 x \,y^{2} a_{3}-393216 x \,y^{2} b_{1}+786432 x \,y^{2} b_{2}-131072 x \,y^{2} b_{3}-131072 y^{3} a_{1}+262144 y^{3} a_{2}-262144 y^{3} a_{3}+524288 y^{3} b_{1}+524288 y^{3} b_{3}-32768 x^{2} a_{1}+65536 x^{2} a_{2}+16384 x^{2} a_{3}+49152 x^{2} b_{1}-81920 x^{2} b_{2}-32768 x^{2} b_{3}+131072 x y a_{1}-262144 x y a_{2}+32768 x y a_{3}-393216 x y b_{1}+131072 x y b_{2}+131072 x y b_{3}-262144 y^{2} a_{1}-131072 y^{2} a_{3}+786432 y^{2} b_{1}-262144 y^{2} b_{2}+32768 x a_{1}-131072 x a_{2}+131072 x b_{2}+65536 x b_{3}-131072 y a_{1}-65536 y a_{3}-524288 y b_{2}-65536 a_{1}-262144 b_{2}}{4096 \left (x^{2}-2 x +8 y +8\right )^{2}} = 0 \] Setting the numerator to zero gives \begin{equation} \tag{6E} -x^{12} a_{3}+12 x^{11} a_{3}-48 x^{10} y a_{3}-60 x^{10} a_{3}+480 x^{9} y a_{3}-960 x^{8} y^{2} a_{3}+192 x^{9} a_{3}-1920 x^{8} y a_{3}+7680 x^{7} y^{2} a_{3}-10240 x^{6} y^{3} a_{3}-320 x^{8} a_{2}-496 x^{8} a_{3}+64 x^{8} b_{3}+4608 x^{7} y a_{3}-23040 x^{6} y^{2} a_{3}+61440 x^{5} y^{3} a_{3}-61440 x^{4} y^{4} a_{3}-256 x^{7} a_{1}+2304 x^{7} a_{2}+1216 x^{7} a_{3}-1024 x^{7} b_{2}-512 x^{7} b_{3}-8192 x^{6} y a_{2}-8192 x^{6} y a_{3}+1024 x^{6} y b_{3}+36864 x^{5} y^{2} a_{3}-122880 x^{4} y^{3} a_{3}+245760 x^{3} y^{4} a_{3}-196608 x^{2} y^{5} a_{3}+1792 x^{6} a_{1}-9728 x^{6} a_{2}-2880 x^{6} a_{3}-1024 x^{6} b_{1}+6144 x^{6} b_{2}+2048 x^{6} b_{3}-6144 x^{5} y a_{1}+43008 x^{5} y a_{2}+12288 x^{5} y a_{3}-24576 x^{5} y b_{2}-6144 x^{5} y b_{3}-73728 x^{4} y^{2} a_{2}-33792 x^{4} y^{2} a_{3}+98304 x^{3} y^{3} a_{3}-245760 x^{2} y^{4} a_{3}+393216 x \,y^{5} a_{3}-262144 y^{6} a_{3}-7680 x^{5} a_{1}+27648 x^{5} a_{2}+4608 x^{5} a_{3}+6144 x^{5} b_{1}-24576 x^{5} b_{2}-6144 x^{5} b_{3}+30720 x^{4} y a_{1}-135168 x^{4} y a_{2}-15360 x^{4} y a_{3}-24576 x^{4} y b_{1}+98304 x^{4} y b_{2}+12288 x^{4} y b_{3}-49152 x^{3} y^{2} a_{1}+245760 x^{3} y^{2} a_{2}-196608 x^{3} y^{2} b_{2}-262144 x^{2} y^{3} a_{2}+16384 x^{2} y^{3} a_{3}-65536 x^{2} y^{3} b_{3}+21504 x^{4} a_{1}-41984 x^{4} a_{2}-7168 x^{4} a_{3}-24576 x^{4} b_{1}+61440 x^{4} b_{2}+11264 x^{4} b_{3}-98304 x^{3} y a_{1}+270336 x^{3} y a_{2}+2048 x^{3} y a_{3}+98304 x^{3} y b_{1}-294912 x^{3} y b_{2}-24576 x^{3} y b_{3}+147456 x^{2} y^{2} a_{1}-491520 x^{2} y^{2} a_{2}+73728 x^{2} y^{2} a_{3}-196608 x^{2} y^{2} b_{1}+393216 x^{2} y^{2} b_{2}-98304 x^{2} y^{2} b_{3}-131072 x \,y^{3} a_{1}+393216 x \,y^{3} a_{2}-163840 x \,y^{3} a_{3}-524288 x \,y^{3} b_{2}+131072 x \,y^{3} b_{3}-262144 y^{4} a_{2}+131072 y^{4} a_{3}-262144 y^{4} b_{3}-30720 x^{3} a_{1}+57344 x^{3} a_{2}+8192 x^{3} a_{3}+57344 x^{3} b_{1}-65536 x^{3} b_{2}-24576 x^{3} b_{3}+188416 x^{2} y a_{1}-212992 x^{2} y a_{2}-294912 x^{2} y b_{1}+458752 x^{2} y b_{2}+32768 x^{2} y b_{3}-294912 x \,y^{2} a_{1}+524288 x \,y^{2} a_{2}-131072 x \,y^{2} a_{3}+393216 x \,y^{2} b_{1}-786432 x \,y^{2} b_{2}+131072 x \,y^{2} b_{3}+131072 y^{3} a_{1}-262144 y^{3} a_{2}+262144 y^{3} a_{3}-524288 y^{3} b_{1}-524288 y^{3} b_{3}+32768 x^{2} a_{1}-65536 x^{2} a_{2}-16384 x^{2} a_{3}-49152 x^{2} b_{1}+81920 x^{2} b_{2}+32768 x^{2} b_{3}-131072 x y a_{1}+262144 x y a_{2}-32768 x y a_{3}+393216 x y b_{1}-131072 x y b_{2}-131072 x y b_{3}+262144 y^{2} a_{1}+131072 y^{2} a_{3}-786432 y^{2} b_{1}+262144 y^{2} b_{2}-32768 x a_{1}+131072 x a_{2}-131072 x b_{2}-65536 x b_{3}+131072 y a_{1}+65536 y a_{3}+524288 y b_{2}+65536 a_{1}+262144 b_{2} = 0 \end{equation} Looking at the above PDE shows the following are all the terms with \(\{x, y\}\) in them. \[ \{x, y\} \] The following substitution is now made to be able to collect on all terms with \(\{x, y\}\) in them \[ \{x = v_{1}, y = v_{2}\} \] The above PDE (6E) now becomes \begin{equation} \tag{7E} \text {Expression too large to display} \end{equation} Collecting the above on the terms \(v_i\) introduced, and these are \[ \{v_{1}, v_{2}\} \] Equation (7E) now becomes \begin{equation} \tag{8E} 65536 a_{1}+262144 b_{2}+\left (21504 a_{1}-41984 a_{2}-7168 a_{3}-24576 b_{1}+61440 b_{2}+11264 b_{3}\right ) v_{1}^{4}+\left (-30720 a_{1}+57344 a_{2}+8192 a_{3}+57344 b_{1}-65536 b_{2}-24576 b_{3}\right ) v_{1}^{3}+\left (32768 a_{1}-65536 a_{2}-16384 a_{3}-49152 b_{1}+81920 b_{2}+32768 b_{3}\right ) v_{1}^{2}+\left (-32768 a_{1}+131072 a_{2}-131072 b_{2}-65536 b_{3}\right ) v_{1}+\left (-262144 a_{2}+131072 a_{3}-262144 b_{3}\right ) v_{2}^{4}+\left (131072 a_{1}-262144 a_{2}+262144 a_{3}-524288 b_{1}-524288 b_{3}\right ) v_{2}^{3}+\left (262144 a_{1}+131072 a_{3}-786432 b_{1}+262144 b_{2}\right ) v_{2}^{2}+\left (131072 a_{1}+65536 a_{3}+524288 b_{2}\right ) v_{2}+\left (-320 a_{2}-496 a_{3}+64 b_{3}\right ) v_{1}^{8}+\left (-256 a_{1}+2304 a_{2}+1216 a_{3}-1024 b_{2}-512 b_{3}\right ) v_{1}^{7}+\left (1792 a_{1}-9728 a_{2}-2880 a_{3}-1024 b_{1}+6144 b_{2}+2048 b_{3}\right ) v_{1}^{6}+\left (-7680 a_{1}+27648 a_{2}+4608 a_{3}+6144 b_{1}-24576 b_{2}-6144 b_{3}\right ) v_{1}^{5}+\left (-98304 a_{1}+270336 a_{2}+2048 a_{3}+98304 b_{1}-294912 b_{2}-24576 b_{3}\right ) v_{1}^{3} v_{2}+\left (-262144 a_{2}+16384 a_{3}-65536 b_{3}\right ) v_{1}^{2} v_{2}^{3}+\left (147456 a_{1}-491520 a_{2}+73728 a_{3}-196608 b_{1}+393216 b_{2}-98304 b_{3}\right ) v_{1}^{2} v_{2}^{2}+\left (188416 a_{1}-212992 a_{2}-294912 b_{1}+458752 b_{2}+32768 b_{3}\right ) v_{1}^{2} v_{2}+\left (-131072 a_{1}+393216 a_{2}-163840 a_{3}-524288 b_{2}+131072 b_{3}\right ) v_{1} v_{2}^{3}+\left (-294912 a_{1}+524288 a_{2}-131072 a_{3}+393216 b_{1}-786432 b_{2}+131072 b_{3}\right ) v_{1} v_{2}^{2}+\left (-131072 a_{1}+262144 a_{2}-32768 a_{3}+393216 b_{1}-131072 b_{2}-131072 b_{3}\right ) v_{1} v_{2}+\left (-8192 a_{2}-8192 a_{3}+1024 b_{3}\right ) v_{1}^{6} v_{2}+\left (-6144 a_{1}+43008 a_{2}+12288 a_{3}-24576 b_{2}-6144 b_{3}\right ) v_{1}^{5} v_{2}+\left (-73728 a_{2}-33792 a_{3}\right ) v_{1}^{4} v_{2}^{2}+\left (30720 a_{1}-135168 a_{2}-15360 a_{3}-24576 b_{1}+98304 b_{2}+12288 b_{3}\right ) v_{1}^{4} v_{2}+\left (-49152 a_{1}+245760 a_{2}-196608 b_{2}\right ) v_{1}^{3} v_{2}^{2}-48 a_{3} v_{1}^{10} v_{2}+480 a_{3} v_{1}^{9} v_{2}-960 a_{3} v_{1}^{8} v_{2}^{2}-1920 a_{3} v_{1}^{8} v_{2}+7680 a_{3} v_{1}^{7} v_{2}^{2}-10240 a_{3} v_{1}^{6} v_{2}^{3}+4608 a_{3} v_{1}^{7} v_{2}-23040 a_{3} v_{1}^{6} v_{2}^{2}+61440 a_{3} v_{1}^{5} v_{2}^{3}-61440 a_{3} v_{1}^{4} v_{2}^{4}+36864 a_{3} v_{1}^{5} v_{2}^{2}-122880 a_{3} v_{1}^{4} v_{2}^{3}+245760 a_{3} v_{1}^{3} v_{2}^{4}-196608 a_{3} v_{1}^{2} v_{2}^{5}+98304 a_{3} v_{1}^{3} v_{2}^{3}-245760 a_{3} v_{1}^{2} v_{2}^{4}+393216 a_{3} v_{1} v_{2}^{5}-a_{3} v_{1}^{12}+12 a_{3} v_{1}^{11}-60 a_{3} v_{1}^{10}+192 a_{3} v_{1}^{9}-262144 a_{3} v_{2}^{6} = 0 \end{equation} Setting each coefficients in (8E) to zero gives the following equations to solve \begin {align*} -262144 a_{3}&=0\\ -245760 a_{3}&=0\\ -196608 a_{3}&=0\\ -122880 a_{3}&=0\\ -61440 a_{3}&=0\\ -23040 a_{3}&=0\\ -10240 a_{3}&=0\\ -1920 a_{3}&=0\\ -960 a_{3}&=0\\ -60 a_{3}&=0\\ -48 a_{3}&=0\\ -a_{3}&=0\\ 12 a_{3}&=0\\ 192 a_{3}&=0\\ 480 a_{3}&=0\\ 4608 a_{3}&=0\\ 7680 a_{3}&=0\\ 36864 a_{3}&=0\\ 61440 a_{3}&=0\\ 98304 a_{3}&=0\\ 245760 a_{3}&=0\\ 393216 a_{3}&=0\\ 65536 a_{1}+262144 b_{2}&=0\\ -73728 a_{2}-33792 a_{3}&=0\\ -49152 a_{1}+245760 a_{2}-196608 b_{2}&=0\\ 131072 a_{1}+65536 a_{3}+524288 b_{2}&=0\\ -262144 a_{2}+16384 a_{3}-65536 b_{3}&=0\\ -262144 a_{2}+131072 a_{3}-262144 b_{3}&=0\\ -8192 a_{2}-8192 a_{3}+1024 b_{3}&=0\\ -320 a_{2}-496 a_{3}+64 b_{3}&=0\\ -32768 a_{1}+131072 a_{2}-131072 b_{2}-65536 b_{3}&=0\\ 262144 a_{1}+131072 a_{3}-786432 b_{1}+262144 b_{2}&=0\\ -131072 a_{1}+393216 a_{2}-163840 a_{3}-524288 b_{2}+131072 b_{3}&=0\\ -6144 a_{1}+43008 a_{2}+12288 a_{3}-24576 b_{2}-6144 b_{3}&=0\\ -256 a_{1}+2304 a_{2}+1216 a_{3}-1024 b_{2}-512 b_{3}&=0\\ 131072 a_{1}-262144 a_{2}+262144 a_{3}-524288 b_{1}-524288 b_{3}&=0\\ 188416 a_{1}-212992 a_{2}-294912 b_{1}+458752 b_{2}+32768 b_{3}&=0\\ -294912 a_{1}+524288 a_{2}-131072 a_{3}+393216 b_{1}-786432 b_{2}+131072 b_{3}&=0\\ -131072 a_{1}+262144 a_{2}-32768 a_{3}+393216 b_{1}-131072 b_{2}-131072 b_{3}&=0\\ -98304 a_{1}+270336 a_{2}+2048 a_{3}+98304 b_{1}-294912 b_{2}-24576 b_{3}&=0\\ -30720 a_{1}+57344 a_{2}+8192 a_{3}+57344 b_{1}-65536 b_{2}-24576 b_{3}&=0\\ -7680 a_{1}+27648 a_{2}+4608 a_{3}+6144 b_{1}-24576 b_{2}-6144 b_{3}&=0\\ 1792 a_{1}-9728 a_{2}-2880 a_{3}-1024 b_{1}+6144 b_{2}+2048 b_{3}&=0\\ 21504 a_{1}-41984 a_{2}-7168 a_{3}-24576 b_{1}+61440 b_{2}+11264 b_{3}&=0\\ 30720 a_{1}-135168 a_{2}-15360 a_{3}-24576 b_{1}+98304 b_{2}+12288 b_{3}&=0\\ 32768 a_{1}-65536 a_{2}-16384 a_{3}-49152 b_{1}+81920 b_{2}+32768 b_{3}&=0\\ 147456 a_{1}-491520 a_{2}+73728 a_{3}-196608 b_{1}+393216 b_{2}-98304 b_{3}&=0 \end {align*}
Solving the above equations for the unknowns gives \begin {align*} a_{1}&=a_{1}\\ a_{2}&=0\\ a_{3}&=0\\ b_{1}&=\frac {a_{1}}{4}\\ b_{2}&=-\frac {a_{1}}{4}\\ b_{3}&=0 \end {align*}
Substituting the above solution in the anstaz (1E,2E) (using \(1\) as arbitrary value for any unknown in the RHS) gives \begin{align*} \xi &= 1 \\ \eta &= -\frac {x}{4}+\frac {1}{4} \\ \end{align*} The next step is to determine the canonical coordinates \(R,S\). The canonical coordinates map \(\left ( x,y\right ) \to \left ( R,S \right )\) where \(\left ( R,S \right )\) are the canonical coordinates which make the original ode become a quadrature and hence solved by integration.
The characteristic pde which is used to find the canonical coordinates is \begin {align*} \frac {d x}{\xi } &= \frac {d y}{\eta } = dS \tag {1} \end {align*}
The above comes from the requirements that \(\left ( \xi \frac {\partial }{\partial x} + \eta \frac {\partial }{\partial y}\right ) S(x,y) = 1\). Starting with the first pair of ode’s in (1) gives an ode to solve for the independent variable \(R\) in the canonical coordinates, where \(S(R)\). Therefore \begin {align*} \frac {dy}{dx} &= \frac {\eta }{\xi }\\ &= \frac {-\frac {x}{4}+\frac {1}{4}}{1}\\ &= -\frac {x}{4}+\frac {1}{4} \end {align*}
This is easily solved to give \begin {align*} y = -\frac {1}{8} x^{2}+\frac {1}{4} x +c_{1} \end {align*}
Where now the coordinate \(R\) is taken as the constant of integration. Hence \begin {align*} R &= \frac {1}{8} x^{2}-\frac {1}{4} x +y \end {align*}
And \(S\) is found from \begin {align*} dS &= \frac {dx}{\xi } \\ &= \frac {dx}{1} \end {align*}
Integrating gives \begin {align*} S &= \int { \frac {dx}{T}}\\ &= x \end {align*}
Where the constant of integration is set to zero as we just need one solution. Now that \(R,S\) are found, we need to setup the ode in these coordinates. This is done by evaluating \begin {align*} \frac {dS}{dR} &= \frac { S_{x} + \omega (x,y) S_{y} }{ R_{x} + \omega (x,y) R_{y} }\tag {2} \end {align*}
Where in the above \(R_{x},R_{y},S_{x},S_{y}\) are all partial derivatives and \(\omega (x,y)\) is the right hand side of the original ode given by \begin {align*} \omega (x,y) &= \frac {x^{6}-6 x^{5}+24 y \,x^{4}+12 x^{4}-96 x^{3} y +192 x^{2} y^{2}-24 x^{3}+96 x^{2} y -384 x \,y^{2}+512 y^{3}+32 x^{2}-128 x y -128 x}{64 x^{2}-128 x +512 y +512} \end {align*}
Evaluating all the partial derivatives gives \begin {align*} R_{x} &= \frac {x}{4}-\frac {1}{4}\\ R_{y} &= 1\\ S_{x} &= 1\\ S_{y} &= 0 \end {align*}
Substituting all the above in (2) and simplifying gives the ode in canonical coordinates. \begin {align*} \frac {dS}{dR} &= \frac {64 x^{2}-128 x +512 y +512}{x^{6}-6 x^{5}+\left (24 y +12\right ) x^{4}+\left (-96 y -8\right ) x^{3}+\left (192 y^{2}+96 y -16\right ) x^{2}+\left (-384 y^{2}+32\right ) x +512 y^{3}-128 y -128}\tag {2A} \end {align*}
We now need to express the RHS as function of \(R\) only. This is done by solving for \(x,y\) in terms of \(R,S\) from the result obtained earlier and simplifying. This gives \begin {align*} \frac {dS}{dR} &= \frac {4 R +4}{4 R^{3}-R -1} \end {align*}
The above is a quadrature ode. This is the whole point of Lie symmetry method. It converts an ode, no matter how complicated it is, to one that can be solved by integration when the ode is in the canonical coordiates \(R,S\). Integrating the above gives \begin {align*} S \left (R \right ) = \int \frac {4 R +4}{4 R^{3}-R -1}d R +c_{1}\tag {4} \end {align*}
To complete the solution, we just need to transform (4) back to \(x,y\) coordinates. This results in \begin {align*} x = \int _{}^{y}\frac {\frac {1}{2} x^{2}-x +4 \textit {\_a} +4}{4 \left (\frac {1}{8} x^{2}-\frac {1}{4} x +\textit {\_a} \right )^{3}-\frac {x^{2}}{8}+\frac {x}{4}-\textit {\_a} -1}d \textit {\_a} +c_{1} \end {align*}
Which simplifies to \begin {align*} x = \int _{}^{y}\frac {\frac {1}{2} x^{2}-x +4 \textit {\_a} +4}{4 \left (\frac {1}{8} x^{2}-\frac {1}{4} x +\textit {\_a} \right )^{3}-\frac {x^{2}}{8}+\frac {x}{4}-\textit {\_a} -1}d \textit {\_a} +c_{1} \end {align*}
This results in \begin {align*} x = \int _{}^{y}\frac {\frac {1}{2} x^{2}-x +4 \textit {\_a} +4}{4 \left (\frac {1}{8} x^{2}-\frac {1}{4} x +\textit {\_a} \right )^{3}-\frac {x^{2}}{8}+\frac {x}{4}-\textit {\_a} -1}d \textit {\_a} +c_{1} \end {align*}
Summary
The solution(s) found are the following \begin{align*} \tag{1} x &= \int _{}^{y}\frac {\frac {1}{2} x^{2}-x +4 \textit {\_a} +4}{4 \left (\frac {1}{8} x^{2}-\frac {1}{4} x +\textit {\_a} \right )^{3}-\frac {x^{2}}{8}+\frac {x}{4}-\textit {\_a} -1}d \textit {\_a} +c_{1} \\ \end{align*}
Verification of solutions
\[ x = \int _{}^{y}\frac {\frac {1}{2} x^{2}-x +4 \textit {\_a} +4}{4 \left (\frac {1}{8} x^{2}-\frac {1}{4} x +\textit {\_a} \right )^{3}-\frac {x^{2}}{8}+\frac {x}{4}-\textit {\_a} -1}d \textit {\_a} +c_{1} \] Verified OK.
\[ \begin {array}{lll} & {} & \textrm {Let's solve}\hspace {3pt} \\ {} & {} & x^{6}+24 y x^{4}-6 x^{5}+192 y^{2} x^{2}-96 x^{3} y+12 x^{4}+512 y^{3}-384 y^{2} x +96 x^{2} y-64 x^{2} y^{\prime }-24 x^{3}-512 y^{\prime } y-128 x y+128 y^{\prime } x +32 x^{2}-512 y^{\prime }-128 x =0 \\ \bullet & {} & \textrm {Highest derivative means the order of the ODE is}\hspace {3pt} 1 \\ {} & {} & y^{\prime } \\ \bullet & {} & \textrm {Solve for the highest derivative}\hspace {3pt} \\ {} & {} & y^{\prime }=\frac {128 x y+24 x^{3}-32 x^{2}+128 x -512 y^{3}-192 y^{2} x^{2}+384 y^{2} x -24 y x^{4}+96 x^{3} y-96 x^{2} y-x^{6}+6 x^{5}-12 x^{4}}{-64 x^{2}-512 y+128 x -512} \end {array} \]
Maple trace
`Methods for first order ODEs: --- Trying classification methods --- trying a quadrature trying 1st order linear trying Bernoulli trying separable trying inverse linear trying homogeneous types: trying Chini differential order: 1; looking for linear symmetries differential order: 1; found: 1 linear symmetries. Trying reduction of order 1st order, trying the canonical coordinates of the invariance group <- 1st order, canonical coordinates successful`
✓ Solution by Maple
Time used: 0.031 (sec). Leaf size: 41
dsolve(diff(y(x),x) = (-128*x*y(x)-24*x^3+32*x^2-128*x+512*y(x)^3+192*x^2*y(x)^2-384*x*y(x)^2+24*y(x)*x^4-96*x^3*y(x)+96*x^2*y(x)+x^6-6*x^5+12*x^4)/(512*y(x)+64*x^2-128*x+512),y(x), singsol=all)
\[ y \left (x \right ) = -\frac {x^{2}}{8}+\frac {x}{4}+\operatorname {RootOf}\left (-x +4 \left (\int _{}^{\textit {\_Z}}\frac {\textit {\_a} +1}{4 \textit {\_a}^{3}-\textit {\_a} -1}d \textit {\_a} \right )+c_{1} \right ) \]
✓ Solution by Mathematica
Time used: 0.311 (sec). Leaf size: 53
DSolve[y'[x] == (-128*x + 32*x^2 - 24*x^3 + 12*x^4 - 6*x^5 + x^6 - 128*x*y[x] + 96*x^2*y[x] - 96*x^3*y[x] + 24*x^4*y[x] - 384*x*y[x]^2 + 192*x^2*y[x]^2 + 512*y[x]^3)/(512 - 128*x + 64*x^2 + 512*y[x]),y[x],x,IncludeSingularSolutions -> True]
\[ \text {Solve}\left [x-16 \text {RootSum}\left [6656 \text {$\#$1}^3-23 \text {$\#$1}-1\&,\text {$\#$1} \log \left (79872 \text {$\#$1}^2-18304 \text {$\#$1}+181 x^2+1448 y(x)-362 x-184\right )\&\right ]=c_1,y(x)\right ] \]