HP 15C and INT(1/√(1-x),0,1)

[Carsen]

Good evening (at least where I live)

I tested your integral on my (hardware) HP 50g. In exact mode, I receive the answer of 2 immediately. In approx. mode on the HP 50g with a fix of 4, I get 1.9999 in a matter of 3 to 4 minutes. I did not time it. I did not use the Equation Writer and I was in RPN mode. I used the integral function that is on the [TAN] key and I built the equation on the stack with RPN. It's fun.

Next I tested your integral on my Dad's (hardware 1987) HP-15C. I entered the equation as such...

1.) LBL 1
2.) 1
3.) SWAP
4.) -
5.) SQRT
6.) 1/x
7.) RTN

I set the HP-15C to a fix of 2 and integrated the integral from 0 to 1. In a time of 2 minutes and 42 seconds, I got the answer of 1.99.
Then I set the 15C to a fix of 4 and attempted to integrate the integral again. In a time of 16 minutes and 28 seconds, I stopped the 15C and didn't get an answer as a result.

I can't give any advice as I am not a proficient user of the HP-15C ONLY because I don't own one yet. But I hope my input on how I solved the integral on my calculators (and my Dad's) proved useful. Oh and I can help with the HP 50g. I would say I am a solid user of the machine.