A106 ==== Does anybody know how to find Fourier series of defined periodical function. I've seen the built-in FFT but I'm not sure how I can use it for this problem. Actually, all I need are amplitudes An of sin(nwt) and cos(nwt). ==== Hi! I recently bought the HP 49G and have some problems with the correct handling now! So please help me to get through it, because I don't have much time left to my next math test!! What must I do to get the limit (or threshold value) of, for instance, lim (x to 1) of (x^2-x)/(x^2-1)? What is the right function of the calculator for this problem and what must I tip in!?!? ==== ==== lim The manual isn't a help, because it's really poor and includes at most 10% of what the calculator could. And I have not found any useful thing in the net yet. So please help me if you can and don't fool me any longer. Best Regards Diz. Content-Type: text/plain; charset=US-ASCII ==== in news yjhx8.186541$vp.2516678@news.chello.at posted 23/04/2002 20:01, Dieter wrote : Ok, but did you try your built-in help ? Limite of a Variable at a Point for a Function : 'LIMIT(Function,Variable=Point)' ... ==== It's at http://www.hpcalc.org/hp49/docs/misc/49g_aug.zip (3.3 MB) That's ok :-) The CAT (catalog) key, just left of EQW. One needs to have at least beta 1.19-1, but naturally everyone has already flashed their ROM to the current 1.19-6 Pressing [NXT] key while in EQW gets you to the next page where the new CAS commands help exists. ==== Sure - you can of course also get help in the catalog (as I said). Beyond that HELP and CASCMD exist. HELP doesn't take any arguments, but launches the CAS help box, and exits with a zero. CASCMD takes one string as argument, for example EXPAND. The difference between CMDS and HELP in the EQW, is that if you highlight a subexpression containing a CAS command, HELP will show directly help for that command, instead of merely showing the list of CAS commands (as CMDS does). ==== I've never used HELP on a subexpression command before! ==== He also needs to update his OS. New 49s come with 1.18, and online help was added in 1.19-something, if I remember correctly. The current (beta) version is 1.19-6b (again, if I remember correctly), but it is no longer on HP's web site. My computer got zapped by a nasty virus, so I no longer have it. ==== : I am trying to use a hp48gx program in a hp49.I found this line IF XLIB 171 90 THEN... and I am trying to use an equivalent line without using a hp48gx xlib. Does anyone what can I use? ==== Are you sure about the 90 ? there's no built-in XLIB 171 90 on the HP48G.. Otherwise, what you can do to find out on how to replace it (you need a HP48G for that, an emulator is fine), Type #aaabbb LIBEVAL on an empty stack where aaa is the command number in hexa (here 90 -> 5A) bbb is the lib number in hexa (here 171-> AB) and look at the error name. Then see just put this name on the HP49. ==== On 23 Apr 2002 02:14:50 -0700, chusor@yahoo.com (Chuso) wrote: XLIB 171 90 ( ROMPTR AB 5A ) is just the user-rpl INFORM command . ==== . I guess that by saying binary you mean log base of 2. You must define a small program to do this, such as << LOG 2 LOG / >> which in approximate mode gets a number (x) from stack and produces the required, log base 2 of x. Instead of LOG (log base 10) you can use LN (log base e)to do the job. ! ==== ln will be on base e and log in base 10. If you want a log in base 2 (which I think you mean by binary) then just use the formula: log(x)/log(2) or ln(x)/ln(2) whatever looks better to you ==== And applying XNUM to the list get reals from integers... - just a note to the newbies (including JYA ;-) Jean-Yves Avenard wrote in message You mean with expand or exploding the list? I'd rather avoid exploding the list, and treating each element of it, since it takes a lot of time. Speed is important in this I think, which is also why POS was a good approach. ==== But XNUM fails for symbolic arguments (which it didn't in the first ROMs), so it's not that easy anymore to add symbolic handling. ==== { 'PI' } HEAD TYPE : 18 { 'PI' } HEAD EVAL TYPE: 9 I just had a look at your original post, and my mistake. What about instead of doing inf POS, you do { inf } HEAD POS, it should work ==== to save time in a loop save the value into a local called 'inf' prior to looping and use that 'inf' instead ==== i just saw one similar to the 32sII in an ad (ISDN magazine) it was all black, and instead of 'ENTER' had 'INPUT,' the letters were green. nice looking! was that a graphic-makeover or a real calc? ==== Is there an hp-48 (or equiv) emulator that i can install without owning the actual calculator? (if needed) where would I find the rom image and then where would i install it in the directory tree? are there any emulators with documentation? i installed x48 into debian 2.2 (potato), but it wants a rom image. even if i were to find the image and put it in the right place, i can find no documentation on the program. The eskimo.com link to a *.tar.gz file is down, but perhaps there are other suitable roms. ==== please take a look at www.hpcalc.org. There are ROM images, too. Be sure to read the docs how to convert the image to a suitable format for any of the emulators. ==== Given the following equation: hf=(3.01*v^1.85)/(c^1.85*d^1.17) Symbolically solve for 'c', the 49g gives solve error: non unary operator. The same is true when using the isol command. Is there a way of symbolically solving these types of equations on the 49g? Also noteworthy is the fact that the ti89, using solve() is able to reduce the above to: c=1.814*[v^1.85/(d^1.17*hf)] I've called HP support, and they acknowledged this issue - but have been able to find a work around. It appears that the 49g's weakness lies in its ability to evaluate exponents. For example try this on the 49g: (x^.258)*(x^.125)=no solution The 89 yeilds: x^.383 I have a feeling that the flag settings may be playing a part in this. Anybody have any ideas ==== Which is (partly) because of the numeric values, hilariously enough. Do XQ on the equation (which is the first thing you want to do, when you want to solve an equation containing numeric values), to get 'hf=301/100*v^(37/20)/(c^(37/20)*d^(117/100))'. Now we can clearly see a problem (if you couldn't before); Although 'c' is only present one single time (hence it should be very easy to isolate), it's to a fractional power. The HP49G turns 'c^(37/20)' into 'c*c^(17/20)' or 'c*EXP(17*LN(c)/20)'. That's a problem, since 'c' is then present at two places. My first thought was this, which solves the equation symbolically in less than 30 seconds: 'hf=(3.01*v^1.85)/(c^1.85*d^1.17)' XQ (to enter the EQW and select the '37/20' part in 'c^(37/20)'. It's very intuitive once you do it) CUT A ENTER (to replace that part with a single variable name, 'A', and return to the stack) 'c' SOLVE 'A' PASTE = SUBST Voila. there are other ways to do it, and the quickest might be to do it manually in the EQW (it took about the same amount of time when I did that, I guess). No, it's 'c=1.814*(v^(1.85)/(d^(1.17)*hf))^(0.541)', and that's not a symbolic solution by the way (the solution provided by the HP above is). My TI89 HW2 spent around 9 minutes finding a symbolic solution, and that solution was not complete. I doubt it - it's one of its forces. Where are LNCOLLECT, EXPLN, LIN, TEXPAND & TSIMP on the TI89? How did you try to simplify it? The HP49G doesn't simplify by itself - you have to tell it in which form you like the result. On the HP49G: '(X^.258)*(X^.125)' XQ LIN (change to numeric mode) LIN EXP2POW -> 'X^.383'. These types of manipulations I find very natural on the '49. It seems odd, but that's the case. i don't think it should have to be THAT difficult - slightly less awkward had been enough ;-) ==== Thanx Steen - you have mastered the 49G CAS, I see! One could also use the (undocumented) STARTEQW http://www.hpcalc.org/details.php?id=4360 which has a POWCOLLECT command, which will give you (.258+.125) X You can now go to the exponent and EVAL the sum, if needed.. ==== . Hum... Yes something is wrong: Change the batteries ! More seriously, the batteries are checked when an interrupt occurs, that is typically when you're pressing a key. So this behavior is perfectly normal. ==== If you really get the message LowBat(S) during normal operation, then it doesn't seem properly operating. Perhaps you try [ON]-[C]? Greetings, ==== You can get the lowbat message not only at the poweron of the calculator. When using KERMIT or XMODEM (on the HP48 and HP49) and on the HP49 when copying data into the Flash port as the batteries are checked at that time and the operation won't be completed if you have low batteries. what about that? << SWAP LIST-> 2 + DUP ROLL @ explode list, roll number to level 1 OVER 3 SWAP @ from 3 to n+2: START OVER ROLL @ get top level element IF OVER 2 MOD @ if least significant bit set THEN ROT ROT @ then leave element on stack ELSE DROP SWAP 1 - SWAP @ else drop it and decrement list size END 2 / IP @ shift number to the right NEXT DROP 2 - ->LIST @ build list >> 105 bytes, cksm 66D7 (on stack) ==== I would use small letters in locals: « -> eq x « eq 'X' x = @ 'X^2' 'X=5' SUBST @ '5^2' EVAL @ 25 eq x @ arguments back » DROP2 @ this is for LASTARG » ==== I've got an HP 48SX and it does not recognize the SUBST command. Is there any equivalent? ==== Try 2 ->LIST | instead of = SUBST ==== there Yes - the Where command (a simple vertical line) is a great SUBSTitute and is used for example when you numerically integrate something on the stack with the Integral sign (elongated S) IIRC Again: « -> eq x « eq 'X' x 2 ->LIST | EVAL eq x » DROP2 » ==== No, it doesn't survive a warmstart (=ON&C). No application does, be that the ON-key is intensionally disabled. Also no supendend programs does, even the content of PICTURE and some flag settings are lost if not saved in STARTUP. That's OK since a warmstart is a kind of (soft) resetting the calculator. ==== in news aa1rv8$4ru$1@namru.matavnet.hu posted 22/04/2002 22:32, vince wrote : Sure it does work... Maybe it's time to update ? (I use latest beta) As (1/X^3)+1 is already in the good form, it is the result the calculator should return... Or did you mistype 1/(X^3+1) ? Then : Into real mode, PARTFRAC answers '1/3/(X+1)-(X-2)/3/(X^2-X+1) Into complexe mode, it says '-((1-i*SQRT(3))/3/(2*X-(1-i*SQRT(3))))+1/3/(X+1)-(1+i*SQRT(3))/3/(2*X-(1+i* SQRT(3)))' ====