This is example of an integral that can't be evaluated using
sage: numerical_integral(i*sin(i*x), x, 0, 0.2)
Traceback (click to the left of this block for traceback)
...
TypeError: unable to coerce to a real number
even though the integrand is real (in disguse). How can I get around this problem?
Your integrand is -sinh(x) and so you can do this using integrate.
f(x)=i*sin(i*x)
print f(x).simplify()
integrate(f(x), x, 0, 0.2)
gives
-sinh(x)
-0.0200667556191
The integrand isn't a real for all (complex) values of x, though. If you wrap the symbolic part in an anonymous function that just does the evaluation (at real values of x in this integral) it will work:
sage: numerical_integral(lambda x: i*sin(i*x), 0, 0.2)
(-0.020066755619075848, 2.2278574117824245e-16)
Asked: 2013-03-06 12:45:59 +0200
Seen: 424 times
Last updated: Mar 06 '13
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