Reintegration problem of abstract function

04112019, 12:44 PM
Post: #1




Reintegration problem of abstract function
Recently I tried to solve the reintegration of some abstract functions with xcas and found some problems.for example:
Code: diff(integrate(integrate(f(sqrt(x^2+y^2)),y,(sqrt(t^2x^2)),sqrt(t^2x^2)),x,t,t),t) Code:
Code:
Related issues Code: ∫(∫(e^((x^2+y^2)/2),y,(sqrt(a^2x^2)),sqrt(a^2x^2)),x,a,a) Code: integrate(sqrt(pi)*1/(sqrt(2))*erf(sqrt(a^2x^2)*exp(ln(2)/2)/2)*exp(x^2/2)sqrt(pi)*1/(sqrt(2))*erf(sqrt(a^2x^2)*exp(ln(2)/2)/2)*exp(x^2/2),x,a,a) In fact, we can get the correct answer through polar transformation. Code: ∫(∫(e^(r^2/2)*r,r,0,a),x,0,2π) Code: 2*pi*(exp(a^2/2)+1) Looking forward to the update of hp prime firmware in 2019 study hard, improve every day 

04252019, 12:20 PM
Post: #2




RE: Reintegration problem of abstract function
Let's take a look at this issue.
study hard, improve every day 

04302019, 07:30 PM
Post: #3




RE: Reintegration problem of abstract function
My only suggestion is to try integration and differentiation one step at a time (inside out). Patience may be needed.
I don't know if turning complex mode off in CAS would help. Eddie. 

04302019, 08:25 PM
Post: #4




RE: Reintegration problem of abstract function  
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