The differential equation for which $\text{y}=\text{a}\cos\text{x}+\text{b}\sin\text{x}$ is a solution, is:
-
$\frac{\text{d}^2\text{y}}{\text{d}\text{x}^2}+\text{y}=0$
-
$\frac{\text{d}^2\text{y}}{\text{d}\text{x}^2}-\text{y}=0$
-
$\frac{\text{d}^2\text{y}}{\text{d}\text{x}^2}+(\text{a}+\text{b})\text{y}=0$
-
$\frac{\text{d}^2\text{y}}{\text{d}\text{x}^2}+(\text{a}-\text{b})\text{y}=0$