ABSTRACT
1 o . A nonhomogeneous linear equation of the fourth order has the form f 4 y x x x x ′ ′ ′ ′ + f 3 y x x x ′ ′ ′ + f 2 y x x ′ ′ + f 1 y x ′ + f 0 y = g ( x ) , f k = f k ( x ) $$ f_{4} y_{xxxx}^{''''} + f_{3} y_{xxx}^{'''} + f_{2} y_{xx}^{''} + f_{1} y_{x}^{'} + f_{0} y = g(x) , f_{k} = f_{k} (x) $$ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315117638/585bf32b-5ab3-4664-8be7-28e9abefef4b/content/math16_1.tif"/>
