# Calculating Integral

 1 f(x) = e**(-x) * log(x+1); uu = integral(f, (x, 0, oo)); uu.n(digits=18) why this dont work? asked Apr 06 '11 Sagud 17 ● 5 ● 7 Kelvin Li 423 ● 9 ● 16

 3 As far as I can tell, this seems to be a bug. uu evaluates to the expression e*expintegral_e(1, 1) and the expintegral_e function doesn't seem to be defined. There is a exponential_integral_1 function which seems to give the correct answer: sage: N(e*exponential_integral_1(1), digits=18) 0.596347362323194107  This agrees with WolframAlpha. posted Apr 06 '11 benjaminfjones 2470 ● 3 ● 33 ● 66 http://bfj7.com/
 2 Yup, @benjaminfjones is right on track. sage: sage.symbolic.pynac.symbol_table['maxima'] {'elliptic_e': elliptic_e, 'imagpart': imag_part, 'acsch': arccsch, 'glaisher': glaisher, 'asinh': arcsinh, 'minf': -Infinity, 'elliptic_f': elliptic_f, '(1+sqrt(5))/2': golden_ratio, 'inf': +Infinity, 'log(2)': log2, 'kron_delta': kronecker_delta, 'asin': arcsin, 'log': log, 'atanh': arctanh, 'brun': brun, '%pi': pi, 'acosh': arccosh, 'sin': sin, 'mertens': mertens, 'ceiling': ceil, 'infinity': Infinity, 'elliptic_ec': elliptic_ec, 'atan': arctan, 'factorial': factorial, 'twinprime': twinprime, 'khinchin': khinchin, 'catalan': catalan, 'signum': sgn, 'binomial': binomial, 'delta': dirac_delta, 'asec': arcsec, 'elliptic_kc': elliptic_kc, '%gamma': euler_gamma, 'realpart': real_part, 'elliptic_eu': elliptic_eu, 'cos': cos, 'acoth': arccoth, 'gamma_incomplete': gamma, 'li[2]': dilog, 'atan2': arctan2, 'exp': exp, 'psi[0]': psi, 'asech': arcsech, 'acos': arccos, 'acot': arccot, 'acsc': arccsc, 'elliptic_pi': elliptic_pi}  We seem to be missing quite a few of the functions at The Maxima special function listing. Fixing this is Ticket #11143. posted Apr 06 '11 kcrisman 6614 ● 13 ● 66 ● 149

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