G.6.2.6 The ctanh functions

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  • ctanh(conj(z)) = conj(ctanh(z))and ctanh is odd.

  • ctanh(+0 + i0) returns +0 + i0.

  • ctanh(x + i (inf)) returns NaN + iNaN and raises the “invalid” floating-point exception, for finite x.

  • ctanh(x + iNaN) returns NaN + iNaN and optionally raises the “invalid” floating- point exception, for finite x.

  • ctanh(+(inf) + iy) returns 1 + i0 sin(2y), for positive-signed finite y.

  • ctanh(+(inf) + i (inf)) returns 1 (+-) i0 (where the sign of the imaginary part of the result is unspecified).

  • ctanh(+(inf) + iNaN) returns 1 (+-) i0 (where the sign of the imaginary part of the result is unspecified).

  • ctanh(NaN + i0) returns NaN + i0.

  • ctanh(NaN + iy) returns NaN + iNaN and optionally raises the “invalid” floating- point exception, for all nonzero numbers y.

  • ctanh(NaN + iNaN) returns NaN + iNaN.