Hi,
The following bit of code correctly computes the triple integral
(64\pi/3) for the volume of an ellipse given by 4x^2 + 4y^2 + z^2=16:
assume(0 < 16 - 4*x**2 - 4*y**2 < 16)
i1 = integral(1,0,sqrt(16 - 4*x**2 - 4*y**2))
show(i1)
assume(0 < 4 - x**2 < 4)
i2 = integral(i1,y,0,sqrt(4 - x**2))
show(i2)
i3 = 8*integral(i2,x,0,2,algorithm='sympy')
show(i3)
If I don't use sympy on the last integral it fails with the following
error message. Anybody know how to give maxima enough information to
solve the problem? -Chris
Traceback (most recent call last): show(i2)
File "", line 1, in <module>
File "/tmp/tmpucDEs9/___code___.py", line 10, in <module>
i3 = _sage_const_8 *integral(i2,x,_sage_const_0 ,_sage_const_2 )
File
"/home/sageserver/sage-5.0/local/lib/python2.7/site-packages/sage/misc/functional.py",
line 728, in integral
return x.integral(*args, **kwds)
File "expression.pyx", line 8745, in
sage.symbolic.expression.Expression.integral
(sage/symbolic/expression.cpp:33707)
File
"/home/sageserver/sage-5.0/local/lib/python2.7/site-packages/sage/symbolic/integration/integral.py",
line 633, in integrate
return definite_integral(expression, v, a, b)
File "function.pyx", line 413, in
sage.symbolic.function.Function.__call__
(sage/symbolic/function.cpp:4678)
File
"/home/sageserver/sage-5.0/local/lib/python2.7/site-packages/sage/symbolic/integration/integral.py",
line 173, in _eval_
return integrator(*args)
File
"/home/sageserver/sage-5.0/local/lib/python2.7/site-packages/sage/symbolic/integration/external.py",
line 21, in maxima_integrator
result = maxima.sr_integral(expression, v, a, b)
File
"/home/sageserver/sage-5.0/local/lib/python2.7/site-packages/sage/interfaces/maxima_lib.py",
line 747, in sr_integral
raise error
RuntimeError: ECL says: Error executing code in Maxima: expt:
undefined: 0 to a negative exponent.
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