For the Euler-Cauchy equation with complex roots m = -1 ± i, which of the following is a correct form of the general real solution?

For the Euler-Cauchy equation with complex roots m = -1 ± i, which of the following is a correct form of the general real solution?

• A. y = x [ C1 cos(ln x) + C2 sin(ln x) ]
• B. y = x^{-2} [ C1 cos(ln x) + C2 sin(ln x) ]
• C. y = x^{-1} [ C1 cos(ln x) + C2 sin(ln x) ]
• D. y = x^{-1} [ C1 cosh(ln x) + C2 sinh(ln x) ]

Answer: (C)