HP 35S, HP 42S

[Albert Chan]

Integral take a long time because u-transformed integral, end-points still not zero.

∫(1/√(4x-x^2), x, 0, 4) = ∫(1/√(1-y^2), y, -1, 1) = ∫(3/√(4-u^2), u, -1, 1)

Here, u-transformation only turned infinite end-points to finite (both ends √3), not 0.
If you integrate u-version instead (i.e. u-transformed once more), problem goes away.

https://www.hpmuseum.org/forum/thread-14...#pid127621