2016-11-19 19:41:37 +0100 received badge ● Scholar (source) 2016-05-10 18:45:22 +0100 received badge ● Famous Question (source) 2016-04-03 20:42:39 +0100 received badge ● Notable Question (source) 2016-04-03 20:42:39 +0100 received badge ● Popular Question (source) 2015-06-29 08:09:44 +0100 commented answer Unable to Simplify to Float Approximation for a Numerical Integral Well... this is really quite confusing. I don't completely understand how getnumerical gets passed a value to be plotted, but I think it's just my unfamiliarity with python; I don't find myself using it often. I appreciate the help, I'm really glad it works now! 2015-06-29 04:54:10 +0100 received badge ● Editor (source) 2015-06-29 04:29:35 +0100 asked a question Unable to Simplify to Float Approximation for a Numerical Integral Hello, I'm trying to approximate a curve, here is my code: a = 1 # x radius length b = 1 # y radius length cut = pi/4 # angle of plane theta = var('theta') phi = var('phi') diffx = diff(a*cos(theta), theta) diffy = diff(b*sin(theta), theta) func = (diffx^2+diffy^2)^(1/2) def getnumerical(i): approx = numerical_integral(func, 0, i) return approx[0] parametric_plot((getnumerical(phi), b*sin(phi)*tan(cut)), (phi, 2*pi, 4*pi), aspect_ratio = 1)  The integral defining the x term in the parametric plot is elliptic, so it must be numerically approximated. So far, I have had little success getting any numerical integral methods to work, including nintegral, and am frustrated because I cannot discern the problem. This implementation gives the error: Traceback (most recent call last): File "", line 1, in File "/tmp/tmpDAHxNF/___code___.py", line 17, in exec compile(u'parametric_plot((getnumerical(phi), b*sin(phi)*tan(cut)), (phi, _sage_const_2 *pi, _sage_const_4 *pi), aspect_ratio = _sage_const_1 ) File "", line 1, in File "/tmp/tmpDAHxNF/___code___.py", line 14, in getnumerical approx = numerical_integral(func, _sage_const_0 , i) File "sage/gsl/integration.pyx", line 332, in sage.gsl.integration.numerical_integral (build/cythonized/sage/gsl/integration.c:3159) File "sage/symbolic/expression.pyx", line 1177, in sage.symbolic.expression.Expression.__float__ (build/cythonized/sage/symbolic/expression.cpp:8897) TypeError: unable to simplify to float approximation  Thank you for any help you provide. Edit: With the constants defined as they currently are, this should plot a sine wave.