A curve has equation $$y = (2q - x^2)(2qx + 3)$$ The gradient of the curve at $x = -1$ is a function of $q$. Find the value of $q$ which minimises the gradient of the curve at $x = -1$.
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A curve has equation
$$y = (2q - x^2)(2qx + 3)$$
The gradient of the curve at $x = -1$ is a function of $q$.
Find the value of $q$ which minimises the gradient of the curve at $x = -1$.