Taylor expanding with the HP50G

[Gil]

I try to get the Taylor expansion of
x/ (4.76 + 0.83*x).

I put the above expression on the stack of the HP50G, then x, then 5 for instance and press TAYLR.

I get the followings message:
TAYLR Error:
Mode switch not allowed here.

Thanks for your help.

[dlidstrom]

It seems the TAYLR command prefers to work with whole numbers for exact answers. You may try a symbolic version of your equation. I substituted your decimals with A and B and it worked fine. To evaluate the equation you need to store the values in A and B respectively.

[Nigel (UK)]

If you don’t want to use extra variables A and B you can replace the decimals with fractions e.g., write 0.83 as 83/100.

Nigel (UK)

[Gil]

Thanks a lot to both of you, the given solutions worked.

I did for instance:
'X/(476/100+83/100*X)' X 5
TAYLR

And got:
'-98476016075/2907915115807744*X^6+1186458025/6109065369344*X^5+-14294675/12834170944*X^4+172225/26962544*X^3+-2075/56644*X^2+25/119*X'

Which command(s) could I use to get, if possible in one single step, the execution of :
98476016075/2907915115807744,
1186458025/6109065369344,
asf?

To get something simplified as
'-(3.38648179721E-5*X^6.+-1.9421269102E-4*X^5.+1.11379808344E-3*X^4.+-6.38756491227E-3*X^3.+3.66322999788E-2*X^2.+-.210084033613*X)'.

[Carsen]

Quote:Which command(s) could I use to get, if possible in one single step, the execution of :
98476016075/2907915115807744,
1186458025/6109065369344,
asf?

To get something simplified as
'-(3.38648179721E-5*X^6.+-1.9421269102E-4*X^5.+1.11379808344E-3*X^4.+-6.38756491227E-3*X^3.+3.66322999788E-2*X^2.+-.210084033613*X)'.

Simply switch to approximate mode and press the [EVAL] key on that object. Hope it helps.

[Steve Simpkin]

(09-29-2023 03:01 AM)Carsen Wrote:  ...
Simply switch to approximate mode and press the [EVAL] key on that object. Hope it helps.

I tried switching the CAS to Approx mode first. When I executed TAYLR, it prompted "Approx. Mode off? YES NO". When I chose NO, it displayed the following error message.

   

[Carsen]

(09-29-2023 04:41 AM)Steve Simpkin Wrote:  I tried switching the CAS to Approx mode first. When I executed TAYLR, it prompted "Approx. Mode off? YES NO". When I chose NO, it displayed the following error message.

Let me explain more clearly.

Execute the TAYLR command in exact mode to get a symbolic answer.

Then switch to approximate mode and press the [EVAL] key on the keyboard to turn the symbolic answer into an approximate one.

[Gil]

Thanks, Carsen.