Question

Number of values of $m\in N$ for which $y=e^{mx}$ is a solution of the differential equation $D^{3}y-3D^{2}y-4Dy+12y=0$, is

• A. 0
• B. 1
• C. 2
• D. more than 2

Answer 1

Answer: (C)

$m^3-3m^2-4m+12=0\Rightarrow m=\pm 2,3$
$m\in N$ hence $m\in \{2,3\}\Rightarrow (C)$