I am undertaking course in digital signal processing. I’ve learned during my undergraduate maths the sinc function i.e. $ $ \text{sinc}(x)=\frac{\text{sin}(x)}{x}$ $ But only now I am actually doing stuff with this function and finding it relevant. Hence my question. Is the function $ $ f(x)=\frac{\text{cos}(x)}{x}$ $ also significant in some areas? Usually sines and cosines go hand to hand hence do we use an original name for it i.e. “cosc”? I looked for it but can’t really find anything about it. No mention about it in Wiki site about sinc function either.