code: public static BigFloat tanh(BigFloat x) {
  		if (x.isNaN() || x.isZero())
  			return x;
  		if (x.isInfinity())
  			return x == POSITIVE_INFINITY ? x.context.ONE : x.context.NEGATIVE_ONE;
  		return x.context.valueOf(BigDecimalMath.tanh(x.value, x.context.mathContext));
  	}
docs: Returns the {@link BigFloat} that is <code>tanh(x)</code>.
  
  @param x the value
  
  @return the resulting {@link BigFloat}
  
  @see BigDecimalMath#tanh(BigDecimal, MathContext)