Помогите хоть с одним из них:

y'' = (e^-y') a a=const

(e^y) dx + (cosy+xe^y) dy=0

Y' + y = e^x

y' + y = 0

y' = - y

dy/dx = - y

dy/y = - dx

ln|y| = - x = const

y = C (e^ (-x)), C - const

y (x) = C (x) (e^ (-x))

y' (x) = C' (x) (e^ (-x)) - C (x) (e^ (-x))

y' + y = e^x

C' (x) (e^ (-x)) - C (x) (e^ (-x)) + C (x) (e^ (-x)) = e^x

C' (x) (e^ (-x)) = e^x

C' (x) = e^2x

C (x) = (1/2) (e^ (2x)) + D

y (x) = C (x) (e^ (-x))

y (x) = D (e^ (-x)) + (1/2) (e^x)