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# Changes

→Second derivative

Here, we need to compute the derivative using first principles, as a limit of a [[difference quotient]]:

<math>\operatorname{sinc}'' 0 := \lim_{x \to 0} \frac{\operatorname{sinc}' x - \operatorname{sinc}' 0}{x - 0} = \lim_{x \to 0} \frac{(x \~~cox ~~cos x - \sin x)/x^2 - 0}{x} = \lim_{x \to 0} \frac{x \cos x - \sin x}{x^3}</math>

The latter limit can be computed in many ways. One way is to use the [[L'Hopital rule]]: