Find the derivative of the following function.
\[
y=\frac{1}{\left(x^{2}-1\right)\left(x^{2}+x+4\right)}
\]
\[
y^{\prime}=
\]

Step 1 ：Given the function \(y=\frac{1}{\left(x^{2}-1\right)\left(x^{2}+x+4\right)}\)

Step 2 ：We are asked to find the derivative of this function.

Step 3 ：We can use the quotient rule and the chain rule to find the derivative.

Step 4 ：The quotient rule states that the derivative of a quotient of two functions is the denominator times the derivative of the numerator minus the numerator times the derivative of the denominator, all over the square of the denominator.

Step 5 ：The chain rule states that the derivative of a composite function is the derivative of the outer function times the derivative of the inner function.

Step 6 ：Applying these rules, we find that the derivative of the function is \(y^{\prime}=-\frac{2x}{\left(x^{2}-1\right)^{2}\left(x^{2}+x+4\right)}+\frac{-2x-1}{\left(x^{2}-1\right)\left(x^{2}+x+4\right)^{2}}\)

Step 7 ：\(\boxed{y^{\prime}=-\frac{2x}{\left(x^{2}-1\right)^{2}\left(x^{2}+x+4\right)}+\frac{-2x-1}{\left(x^{2}-1\right)\left(x^{2}+x+4\right)^{2}}}\) is the final answer.