练习53 一.2,D,Ps(x-3 12 .3.卩=ch(x+c1)+C2, y=sh(+c y"=ch(x+cu), y)2=ch2(x+c1)=1+sh2(x+c)=1+(y) 故所求微分方程为: n2=1+(y K心练习5.3 一. 2. , 12 3 x y = . 6 1 12 ( 2) 3 + − = x y 一. 3. ch( ) , 1 2 y = x + c + c sh( ), 1 y = x + c ch( ), 1 y = x + c ( ) ( ) 1 2 1 2 2 ( y ) = ch x + c = 1 + sh x + c 2 = 1 + ( y) 故所求微分方程为: ( ) 1 ( ) . 2 2 y = + y