1yyy2Solution1yyy2 1yd2ydx2dydx2 let dydxv d2ydx2dvdx d2ydx2
(1+y)y\'\'=(y\')^2
Solution
(1+y)y\'\'=(y\')^2
(1+y)d2y/dx2=(dy/dx)2
let dy/dx=v
d2y/dx2=dv/dx
d2y/dx2=dv/dy *dy/dx
d2y/dx2=dv/dy *v
(1+y)y\'\'=(y\')2
(1+y)dv/dy *v=(v)2
(1+y)dv/dy =v
dv/v =dy/(1+y)
integrate on both sides
dv/v =dy/(1+y)
ln(v)=ln(1+y) +c
v=eln(1+y) +c
v=eln(1+y)ec
v=C(1+y)
dy/dx=C(1+y)
dy/(1+y) =Cdx
integrate on both sides
dy/(1+y) =Cdx
ln(1+y)=Cx +D
(1+y)=eCx +D
(1+y)=DeCx
y =DeCx -1 where C,D are constants
