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sage doesn't evaluate

asked 2015-10-14 08:49:11 -0500

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If I say f(x) = sum(k,k,0,x) and then f(2), I get 3, of course, but if I say g(x) = (binomial(10,k),k, 0,x) and then g(2), sage doesn't evaluate, just returns the definition with x replaced by 2. Why? Thanks

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answered 2015-10-15 01:35:31 -0500

updated 2015-10-15 01:36:02 -0500

Use simplify_full:

sage: f(x) = sum(k,k,0,x)
sage: f
x |--> 1/2*x^2 + 1/2*x
sage: f(x) = sum(binomial(10,k),k, 0,x)
sage: f
x |--> sum(binomial(10, k), k, 0, x)
sage: f(2)
sum(binomial(10, k), k, 0, 2)
sage: f(2).simplify_full()
56
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Maybe I'm using an older version. The answer I get for f(2).simplify_full() is 3628800 * sum(1/(factorial(k) * factorial(-k + 10)), k,0,2)

mariopablo gravatar imagemariopablo ( 2015-10-15 07:11:13 -0500 )edit

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Asked: 2015-10-14 08:49:11 -0500

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Last updated: Oct 15 '15