e 7 : solve the following differential equation :
\[
y^{\prime \prime}-y=0
\]
\(\boxed{y(x) = C_1 e^{-x} + C_2 e^{x}}\)
Step 1 :Find the characteristic equation: \(r^2 - 1 = 0\)
Step 2 :Find the roots: \(r_1 = -1\) and \(r_2 = 1\)
Step 3 :Write the general solution: \(y(x) = C_1 e^{-x} + C_2 e^{x}\)
Step 4 :\(\boxed{y(x) = C_1 e^{-x} + C_2 e^{x}}\)