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# Error in integral

I've got this error on the second integral. I put the code on wxMaxima and returned sucessfull. On wxMaxima, raise a question "z is positive, negative or zero?", also on sage, but on sage I can't answer that. How can I correct this?

x,y,z = var("x y z")

function = x*e^(-y)

integral(function,y,0,ln(x)).integral(x,0,2*z)

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## 1 answer

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You can add some assumption:

sage: assume(z > 0)
sage: integral(function,y,0,ln(x)).integral(x,0,2*z)
2*z^2 - 2*z

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## Comments

A few alternatives :

sage: with assuming(z>0): integral(function,y,0,ln(x)).integral(x,0,2*z)
2*z^2 - 2*z
sage: with assuming(z<0): integral(function,y,0,ln(x)).integral(x,0,2*z)
2*z^2 - 2*z
sage: integral(function,y,0,ln(x)).integral(x,0,2*z, algorithm="sympy")
2*z^2 - 2*z
sage: integral(function,y,0,ln(x)).integral(x,0,2*z, algorithm="giac")
2*z^2 - 2*z
sage: integral(function,y,0,ln(x)).integral(x,0,2*z, algorithm="fricas")
2*z^2 - 2*z

( 2020-08-25 12:55:05 -0600 )edit

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Asked: 2020-08-25 08:50:58 -0600

Seen: 48 times

Last updated: Aug 25