Interesting rounding results.

Walter said the WP43S returns -1.045787917714882796046987298089874

on the DM42:

18 [ENTER] 11 [/] 11 [1/x] [y^x] returns 1.045787917714882796046987298089873

18 [ENTER] 11 [/] [+/-] 11 [1/x] [y^x] [complex] [x^2] [x<>y] [x^2] [+] [SQRT] returns 1.045787917714882796046987298089872

## Question about a result

### Re: Question about a result

My programmable calculators - former: CBM PR100, HP41CV, HP28S, HP11C - current: HP48G(+), HP35S, DM41X, DM42

- Over_score
**Posts:**115**Joined:**Fri May 05, 2017 9:37 pm**Location:**France

### Re: Question about a result

The correct answer is : https://www.wolframalpha.com/input/?i=- ... 82%2F11%29

-1.045787917714882796046987298089

So the correctly rounded result to 34 digits is -1.045787917714882796046987298089

Thus, the WP43S shows THE correct result.

-1.045787917714882796046987298089

**8735**86767669934361619669582805400....So the correctly rounded result to 34 digits is -1.045787917714882796046987298089

**874**Thus, the WP43S shows THE correct result.

DM42 SN00284 running free42 &

**SN03835 running WP43S**, DM15L, HP41CV, HP42S, HP35s, WP34S, HP Prime### Re: Question about a result

What and who else?Over_score wrote: ↑Tue Jan 19, 2021 7:13 pmSo the correctly rounded result to 34 digits is -1.045787917714882796046987298089874

Thus, the WP43S shows THE correct result.

DM42 SN: 00041 β

HP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L

**WP 43S running**on this deviceHP-35, HP-45, ..., HP-35S, WP 34S, WP 31S, DM16L

### Re: Question about a result

or you can say the 42 truncates and the 43 rounds

My programmable calculators - former: CBM PR100, HP41CV, HP28S, HP11C - current: HP48G(+), HP35S, DM41X, DM42

- Stefan Karlsson
**Posts:**22**Joined:**Thu Apr 04, 2019 10:26 pm

### Re: Question about a result

To add to the list of HP calculators that have the \(\sqrt[x]{y}\) function and return the real result : HP 32SII.

The solver in DM42 will return the real result (but is of course more complicated to use).

Edit 1: Grammar.

Edit 2: The DM42 solver

The solver in DM42 will return the real result (but is of course more complicated to use).

Edit 1: Grammar.

Edit 2: The DM42 solver

**will**find the real result.
Last edited by Stefan Karlsson on Tue Jan 19, 2021 9:44 pm, edited 1 time in total.

### Re: Question about a result

Well, the other way is to look at the roots from the complex point of view, knowing that all roots are on the circle with the same radius as the real root, and knowing that one root will be negative, or at 180°.jant wrote: ↑Sun Jan 17, 2021 1:09 pm\(\begin{eqnarray}

x^{11} &=& -\frac{18}{11}

\end{eqnarray}\)

Trying to calculate the result for x should give me the real number \(\begin{eqnarray}x \cong -1,046\end{eqnarray}\).

My DM42/Free42 gives me the complex result \(\begin{eqnarray}x \cong 1,0034 + 0,2946i\end{eqnarray}\).

if you do get a complex root using the way of powers as was discussed above,

Code: Select all

`18 ENTER 11 / +/- 11 1/X Y^X`

Code: Select all

`POLAR`

Code: Select all

`COMPLEX X<>Y SHOW`

**874**(WP43S / C43) with exactly the same rounding as before. I also fetched my WP34C from the drawer and confirm in double complex mode, the result is the same, ...

**874**. Also checked WP34S on iPhone, also ...

**874**. The DM42 and Free42 on my iPhone both render 1.045787917714882796046987298089

**872**. (How I do like the DM42 skin of Free42 on the iPhone ... )

Jaco Mostert

Elec Eng, South Africa

Elec Eng, South Africa

**C43 (WP34C) on DM42 sn. 03818 & 06199**for complex math, HP42S; HP32Sii, WP34S&C, HP28C, HP35s, EL-506P, EL-W506, PB700; owned FX702P & 11C; used HP67 & HP85; iOS:**42s Byron**, Free42, WP31S/34S, HCalc.