Bill Allombert on Mon, 19 Nov 2018 20:03:25 +0100 |
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Re: apply(sign,x) == x |
On Mon, Nov 19, 2018 at 06:38:35PM +0000, Jacques Gélinas wrote: > apply(f, A): If A is a polynomial or power series, apply f on all coefficients. the coefficients of x are 0 and 1, so apply(sign,x) = sign(0)*x^0+sign(1)*x == x > Of course, I would expect sign not to return a polynomial, but -1, 0, or 1 as in > apply(sign,Vec(x)) == [1,0] [1,0] is neither -1, 0 or 1 ! Cheers, Bill.