From: Richard F. <fa...@gm...> - 2024-02-25 22:08:49
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Consider these definitions: u(x):= 2*x/(1+x)$ v(x):= 2- (2/x)/(1+1/x)$ w(x):= (1+u(x)^2)/(2+u(x)^2)$ y(x):= (1+v(x)^2)/(2+v(x)^2)$ z(x):= 1-1/(2+v(x)^2)$ ll(x):= [u(x),v(x),w(x),y(x),z(x)]$ Now if we try: ratsimp(ll); we see that u=v, w=y=z as rational functions. try ll(1/2) for instance. Looks OK. but ll(0) fails with expt: undefined 0 to a negative exponent. . If you load my infinity.lisp file and try ll(rat(0)) you get [0, indef, 1/2,indef, oo] ... This example comes from https://people.eecs.berkeley.edu/~wkahan/UnumSORN.pdf RJF |