An HP48/49 CAS question  Printable Version + HP Forums (https://archived.hpcalc.org/museumforum) + Forum: HP Museum Forums (https://archived.hpcalc.org/museumforum/forum1.html) + Forum: Old HP Forum Archives (https://archived.hpcalc.org/museumforum/forum2.html) + Thread: An HP48/49 CAS question (/thread44483.html) 
An HP48/49 CAS question  Valentin Albillo  10172003 Hi everybody. Not owning any HP48/49 model, there's no immediate way for me to test this, so I'd appreciate if any of you HP48/49 owners would try this for me and post here the results.
The question is: what result does the HP48/49 symbolic algebra system produce for the following indefinite integral: Integral[ sin(x^n) . dx ]where n is a constant ? Specifically, I'm interested to know if it does produce some kind of exact closed result, in terms of known functions (elementary or not). I'm not interested in Taylorseriesexpansion based results or any other nonclosed approximations (not to mention purely numerical results). In case it can't produce a closed result for general, arbitrary n, I would then be interested to know if it can produce a closed result for some particular values of n, and if so, the specific values of n it can solve. I would expect it to be able to produce a closed result for n = 0 and n = 1 at the very least, but what about other values of n, both integer and noninteger (n = 2, 3, ..., 1/2, 1/3, ...) ? What about negative values of n (n = 1, 2, ..., 1/2, ...) ?
Thanks in advance for any results or comments and best regards from V.
Re: An HP48/49 CAS question  Werner Huysegoms  10172003 Hi Valentin.
Cheers, Werner
Re: An HP48/49 CAS question  Valentin Albillo  10172003 Werner posted: "The 49 cannot solve any but the most trivial of these integrals (ie with N=0 or 1). All the rest are simply returned in integral form."
Best regards from V.
Re: An HP48/49 CAS question  rolando  10172003 ValentÃn:
INTVX(SIN(X^N)) = INT(SIN(EXP(N*LN(X))) I did no try the IBP (integration by parts) command because the function to be integrated must be expressed as a product of functions. The ROM in the emulator was 1.18 It seems that this is too much for the HP49G CAS. Rolando
Re: An HP48/49 CAS question  hugh  10172003 you're expecting a bit much arent you. these integratals are mostly only in terms of special functions (like complex gamma, sinc, and fresnel) which arent even there. except for the cases n = 0, 1 and 1/2. interstingly the case n = 1, is close to one of my numerical tests: integrate(cos(1/x), 0, 1) numerically or otherwise. so far no calculator has even got close (0.0844109505)
Re: An HP48/49 CAS question  hugh  10172003 there's some more. 1/m (m = 1,2...) are also representable since int(sin(x^n), dx) can be solved when int(x^n sin(x), dx) is soluble. i'd be interested to know if these come out of the 48/49, using alg48, for example.
Re: An HP48/49 CAS question  Werner Huysegoms  10202003 Hi Valentin. I did use a real 49G in the process: The Xt stuff is a change of variable and the 4x's way of saying it can't solve the integral.
Cheers, Werner Re: An HP48/49 CAS question  Valentin Albillo  10202003 Thanks Werner, it's more or less what I expected and what would be reasonable, by the way. The fact that it manages to solve the n=1/2 case is encouraging. I've always been somewhat amazed by the fact that sin(sqrt(x)) is elementarily integrable while sin(x^2) is not. One would tend to expect exactly the opposite, as the square root function seems more 'irrational', so to speak, than the simple, polynomial, 'square' function :)
Best regards from V.
