Passo 4.5

/**
		 * Cálculo de B(x,t)
		 */
		System.out.println("\n***************************************************");
		System.out.println("******************PASSO 4.5 Cálculo de B(x,t)******");
		System.out.println("***************************************************\n");
		
		BigDecimal Bxt = BigDecimal.ZERO;
		BigDecimal x = BigDecimal.ZERO;
		BigDecimal t = new BigDecimal("365").setScale(30, RoundingMode.HALF_EVEN);
		
		/**
		 * Convertendo valor de v para m/d
		 */
		BigDecimal Vmd = v.multiply(new BigDecimal(Math.pow(10d, -2d))).setScale(30, RoundingMode.HALF_EVEN); 
		System.out.println("Valor de Vmd (1,96E-03): " + nb.format(Vmd));
		
		/**
		 * convertendo valor de W para m/d
		 */
		BigDecimal Wmd = W.divide(new BigDecimal("100"), MathContext.DECIMAL128).setScale(30, RoundingMode.HALF_EVEN);
		System.out.println("Valor de Wmd (2,39E-03): " + nb.format(Wmd));

		/**
		 * Convertendo DX para m³/d
		*/
		BigDecimal Dxm3d = Dx.divide(new BigDecimal("10000")).setScale(30, RoundingMode.HALF_EVEN);
		System.out.println("Valor de Dxm3d (3,99E-04): " + nb.format(Dxm3d));

		System.out.println("Valor de R (2,79E+00): " + nb.format(R));
		
		while (x.compareTo(Xm) <= 0) {
		
			/**
	 		* Cálculo do Primeiro Termo
			*/
			BigDecimal primeiroTermo = (Vmd.subtract(Wmd).multiply(x)).divide(Dxm3d.multiply(new BigDecimal(2d)), 20, RoundingMode.HALF_UP);
			System.out.println("valor do primeiro termo: " + nb.format(primeiroTermo));
				
			/**
			 * Cálculo do segundoTermo
			 */
			//R.x - w.t
			BigDecimal dividendo = R.multiply(x).subtract(Wmd.multiply(t));
			BigDecimal dois = new BigDecimal("2").setScale(20);
			//2 . (D.R.t) ^ 1/2
			BigDecimal divisor = new BigDecimal(Math.sqrt(Dxm3d.multiply(R).multiply(t).doubleValue())).multiply(dois);
			BigDecimal segundoTermo = dividendo.divide(divisor, MathContext.DECIMAL128).setScale(30, RoundingMode.HALF_EVEN);
			System.out.println("valor do segundo termo (-0,685292516): " + segundoTermo.setScale(9, RoundingMode.HALF_EVEN));
				
			/**
			 * Cálculo do terceiroTermo
			 */
			BigDecimal terceiroTermo =  (Vmd.add(Wmd).multiply(x)).divide(Dxm3d.multiply(new BigDecimal(2d)),20,RoundingMode.HALF_EVEN);
			System.out.println("valor do terceiro termo (0,00E+00): " + nb.format(terceiroTermo));
	
			/**
			 * Cálculo do quartoTermo
			 */
			BigDecimal quartoTermo = (R.multiply(x).add(Wmd.multiply(t)).divide((bigSqrt(Dxm3d.multiply(R).multiply(t)).multiply(dois)), MathContext.DECIMAL128).setScale(30, RoundingMode.HALF_EVEN));
			System.out.println("valor do quartoTermo termo (0,685292516):" + quartoTermo.setScale(9, RoundingMode.HALF_EVEN));
				
			BigDecimal divisao = new BigDecimal(1d/2d);
				
			BigDecimal BxtFinal = (divisao.multiply(new BigDecimal(Math.exp(primeiroTermo.doubleValue()))).
						multiply(new BigDecimal(Erf.erfc(segundoTermo.doubleValue()))).add((divisao)
				       .multiply(new BigDecimal(Math.exp(terceiroTermo.doubleValue())))
				       .multiply(new BigDecimal(Erf.erfc(quartoTermo.doubleValue())))));
			
			System.out.println("Valor total de Bxt em BigDecimal: " + nb.format(BxtFinal));

			x = x.add(new BigDecimal("0.8"));
			System.out.println("==> Valor de x : " + x);
		}