airy_dai does not produce a bigfloat, but only a double. See
(%i37) fpprec:40$
(%i38) airy_dai(1.5d0);
(%o38) -0.09738201284230132
(%i39) ?print(%);
-0.09738201284230132
build_info(version="5.47.0",timestamp="2023-06-02 20:31:42",host="x86_64-w64-mingw32",lisp_name="SBCL",.....
I think you have a typo there. You wrote
1.5d0
. You probably wanted1.5b0
. Then I get: