Question: Hyperbolic functions of intervals

ii := evalr(csch(INTERVAL(-infinity .. -1, 1 .. infinity)));
             INTERVAL(-csch(1) .. 0, csch(1) .. 0)

evalr(ii-ii);
                            -csch(1)

(Make sure you don't have the Typesetting level set to Extended, or ii won't be displayed correctly.)

There are no functions to test for interval membership (or to compute intersections/unions of intervals), so it's unclear how Maple treats the interval csch(1)..0, but apparently evalr is getting tripped up by it.

Also:

evalr(sech(INTERVAL(-infinity .. -1, 1 .. infinity)));
                               0

evalr(arccsch(INTERVAL(-infinity .. -1, 1 .. infinity)));
Error, (in evalr/arccsch) too many levels of recursion

 

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