cálculo de error para \(\eta\)
\(\eta=\frac{2}{9}\frac{gr\left(\rho_e-\rho_{liq}\right)}{v_{\lim}}\)
\(\bigtriangleup\eta=\sqrt{\left(\frac{\delta\eta}{\delta g}\bigtriangleup g\right)^2+\left(\frac{\delta\eta}{\delta\rho_e}\bigtriangleup\rho_e\right)^2+\left(\frac{\delta\eta}{\delta\rho_{liq}}\bigtriangleup\rho_{liq}\right)^2+\left(\frac{\delta\eta}{\delta r}\bigtriangleup r\right)^2+\left(\frac{\delta\eta}{\delta v_{\lim}}\bigtriangleup v_{\lim}\right)^2}\)