[Bug or Suggestion]About HP Prime G1 New Beta Firmware

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Related issues

Code:

∫(∫(e^(-(x^2+y^2)/2),y,-(sqrt(a^2-x^2)),sqrt(a^2-x^2)),x,-a,a)

The answer from XCAS

Code:

integrate(sqrt(pi)*1/(sqrt(2))*erf(sqrt(a^2-x^2)*exp(ln(2)/2)/2)*exp(-x^2/2)-sqrt(pi)*1/(sqrt(2))*erf(-sqrt(a^2-x^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)

Get the answer

Code:

2*pi*(-exp(-a^2/2)+1)