Hi there,

$\displaystyle (d^2y)/(dx^2) + 4y = 0$ is obviously the second derivative.

What I know is that if its $\displaystyle dy/dx$ I must separate the dy and only the y to one side , and the x's and any number attached to the y along with dx to the other side ( other side of the = sign ). After that is done, we integrate both sides to find the answer. Okay sweet, but how do we apply that on the second derivative ?

Thank you