MatemáticasAvanzado1 respuestas

Y'' + 3 / xy' + 4x ^ 2y = 0ecuacion diferencial por metodo de frobeniuses urgente?

Y'' + 3 / xy' + 4x ^ 2y = 0 ecuacion diferencial por metodo de frobenius es urgente!

En resumen

Bueno yo lo haré por otro método quizá te sirva después. Lo que trataré de hacer es llevar la ecuación a la forma de Bessel. Sea la ecuación (1)<img src="https://tex.z-dn.net/?

Mejor respuesta

Manuelgomez1193
9

Bueno yo lo haré por otro método quizá te sirva después.

Lo que trataré de hacer es llevar la ecuación a la forma de Bessel.

Sea la ecuación (1)<img src="https://tex.z-dn.net/?f=xy%27%27%2B3y%27%2B4x%5E3y%3D0" /> entonces hagamos el siguiente cambio de variable<img src="https://tex.z-dn.net/?f=y%3Dp%28x%29%5Ccdot%20q%28x%29" /> así tenemos

<img src="https://tex.z-dn.net/?f=y%27%3Dp%27q%2Bpq%27%5C%5C%20%5C%5C%0Ay%27%27%20%3Dp%27%27q%2B2p%27q%27%2Bpq%27%27" />

Reemplazamos esto en la EDO (1)

<img src="https://tex.z-dn.net/?f=x%28p%27%27q%2B2p%27q%27%2Bp%27q%27%27%29%2B3%28p%27q%2Bpq%27%29%2B4x%5E3pq%3D0%5C%5C%20%5C%5C%0Axp%27%27q%2B%282xq%27%2B3q%29p%27%2B%28xpq%27%27%2B3pq%27%2B4x%5E3pq%29%3D0%5C%5C%20%5C%5C%0A%5Ctexttt%7Bdividimos%20entre%20%7Dq%5C%5C%20%5C%5C%0Axp%27%27%2B%5Cleft%28%5Cdfrac%7B2xq%27%2B3q%7D%7Bq%7D%5Cright%29p%27%2B%5Cleft%28%5Cdfrac%7Bxq%27%27%2B3q%27%2B4x%5E3q%7D%7Bq%7D%5Cright%29p%3D0%5C%5C%20%5C%5C%0A%5Ctexttt%7Bmultiplicamos%20por%20%7Dx%5C%5C%20%5C%5C%0Ax%5E2p%27%27%2B%5Cleft%28%5Cdfrac%7B2xq%27%2B3q%7D%7Bq%7D%5Cright%29p%27x%2B%5Cleft%28%5Cdfrac%7Bx%5E2q%27%27%2B3xq%27%2B4x%5E4q%7D%7Bq%7D%5Cright%29p%3D0%5C%5C%20%5C%5C%20%5C%5C%0A%5Ctexttt%7BNos%20conviene%20que%20%7D%5Cdfrac%7B2xq%27%2B3q%7D%7Bq%7D%3D1%5Ctexttt%7B%20se%20puede%20hacer%20esto%20%7D%5C%5C%5Ctexttt%7Bya%20que%20estamos%20en%20plena%20construcci%5C%27on%20de%20las%20funciones%7D%5C%5Cp%5Ctexttt%7B%20y%20%7Dq%0A" />

<img src="https://tex.z-dn.net/?f=%5Ctexttt%7Bentonces%20resolvemos%20%7D%5C%5C%20%5C%5C%0A%5Cdfrac%7B2xq%27%2B3q%7D%7Bq%7D%3D1%5C%5C%20%5C%5C%0Axq%27%3D-q%5C%5C%20%5C%5C%0Aq%3D%5Cdfrac%7B1%7D%7Bx%7D%5C%5C%20%5C%5C%20%5C%5C%0A%5Ctexttt%7BReemplazamos%20esto%20en%20la%20EDO%3A%20%7D%5C%5C%20%5C%5C%0Ax%5E2p%27%27%2B%5Cleft%28%5Cdfrac%7B2xq%27%2B3q%7D%7Bq%7D%5Cright%29p%27x%2B%5Cleft%28%5Cdfrac%7Bx%5E2q%27%27%2B3xq%27%2B4x%5E4q%7D%7Bq%7D%5Cright%29p%3D0%5C%5C%20%5C%5C%20%5C%5C%0Ax%5E2p%27%27%2Bp%27x%2B%284x%5E4-1%29p%3D0%5C%5C%20%5C%5C%0A%5Ctexttt%7BHacemos%20otro%20cambio%20de%20variable%20%7Du%3Dx%5E2%5Ctexttt%7B%20note%20que%20las%7D%5C%5C%0A%5Ctexttt%7Blas%20derivadas%20de%20%7Dp%5Ctexttt%7B%20son%20relativas%20a%20la%20variable%20%7Dx%5Ctexttt%7B%20por%20ello%7D%5C%5C%20%5C%5C%0A%5Cdfrac%7Bdp%7D%7Bdx%7D%3D%5Cdfrac%7Bdp%7D%7Bdu%7D%5Ccdot%20%5Cdfrac%7Bdu%7D%7Bdx%7D%3D2x%5Ccdot%5Cdfrac%7Bdp%7D%7Bdu%7D" />

<img src="https://tex.z-dn.net/?f=%5Cdfrac%7Bd%5E2p%7D%7Bdx%5E2%7D%3D2%5Ccdot%5Cdfrac%7Bdp%7D%7Bdu%7D%2B4u%5Ccdot%5Cdfrac%7Bd%5E2p%7D%7Bdu%5E2%7D" />

<img src="https://tex.z-dn.net/?f=%5Ctexttt%7BReemplazando%20en%20%7Dx%5E2p%27%27%2Bp%27x%2B%284x%5E4-1%29p%3D0%5Ctexttt%7B%20tenemos%3A%20%7D%5C%5C%20%5C%5C%20%5C%5C%0Au%5E2p%27%27%2Bup%2B%5Cleft%28u%5E2-%5Cdfrac%7B1%7D%7B4%7D%5Cright%29p%3D0%5C%3B%5C%3B%5C%3B%5C%3B%5C%3B%5Ctexttt%7B%20%28Ecuaci%5C%27on%20de%20Bessel%29%7D%5C%5C%20%5C%5C%20%5C%5C%0A%5Ctexttt%7Bcuya%20soluci%5C%27on%20es%3A%20%7D%20p%3DC_1J_%7B1%2F2%7D%28u%29%2BC_2J_%7B-1%2F2%7D%28u%29%5Ctexttt%7B%20recuerde%20que%20%7D%5C%5C%20y%3D%20pq%20%3D%5Cdfrac%7Bp%7D%7Bx%7D%5Ctexttt%7B%20y%20%7Du%3Dx%5E2%5Ctexttt%7B%20entonces%3A%7D%5C%5C%20%5C%5C%20%5C%5C%0Ay%3D%5Cdfrac%7BC_1%7D%7Bx%7DJ_%7B1%2F2%7D%28x%5E2%29%2B%5Cdfrac%7BC_2%7D%7Bx%7DJ_%7B-1%2F2%7D%28x%5E2%29" />

<img src="https://tex.z-dn.net/?f=%5Ctexttt%7Bes%20decir%3A%7D%5C%5C%20%5C%5C%20%5C%5C%0A%5Cdisplaystyle%0Ay%3D%5Cdfrac%7BC_1%7D%7Bx%7D%5Csum_%7Bn%3D0%7D%5E%7B%5Cinfty%7D%5Cdfrac%7B%28-1%29%5En%7D%7B%5CGamma%28n%2B1%29%5CGamma%28n%2B1%2B1%2F2%29%7D%5Cleft%28%5Cdfrac%7Bx%5E2%7D%7B2%7D%5Cright%29%5E%7B2n%2B1%2F2%7D%2B%5Ccdots%5C%5C%20%5C%5C%5C%5C%2B%5Cdfrac%7BC_2%7D%7Bx%7D%5Csum_%7Bn%3D0%7D%5E%7B%5Cinfty%7D%5Cdfrac%7B%28-1%29%5En%7D%7B%5CGamma%28n%2B1%29%5CGamma%28n%2B1-1%2F2%29%7D%5Cleft%28%5Cdfrac%7Bx%5E2%7D%7B2%7D%5Cright%29%5E%7B2n-1%2F2%7D%0A" />

<img src="https://tex.z-dn.net/?f=%5Ctexttt%7Busemos%20la%20propiedad%3A%20%7D%5C%5C%20%5C%5C%0A%5CGamma%28z%29%5CGamma%5Cleft%28z%2B%5Cdfrac%7B1%7D%7B2%7D%5Cright%29%3D2%5E%7B1-2z%7D%5Csqrt%7B%5Cpi%7D%5C%2C%5CGamma%282z%29%5C%5C%20%5C%5C%20%5C%5C%0A%5Ctexttt%7BAs%5C%27i%20%3A%20%7D%5C%5C%20%5C%5C%0AJ_%7B1%2F2%7D%3D%5Cdfrac%7B%5Csin%28x%5E2%29%7D%7Bx%5Csqrt%7B2%5Cpi%7D%7D%5Ctexttt%7B%20y%20%7DJ_%7B-1%2F2%7D%3D%5Cdfrac%7B%5Ccos%28x%5E2%29%7D%7Bx%5Csqrt%7B2%5Cpi%7D%7D%5C%5C%20%5C%5C%5Ctext%7Bpor%20ende%3A%20%7D%5C%5C%20%5C%5C%20%5C%5C%0A%5Cboxed%7B%5Cboxed%7By%3Dc_1%5Cdfrac%7B%5Csin%28x%5E2%29%7D%7Bx%5E2%7D%2Bc_2%5Cdfrac%7B%5Ccos%28x%5E2%29%7D%7Bx%5E2%7D%7D%7D" />.