Question about Solve
08-25-2015, 07:16 AM (This post was last modified: 08-25-2015 07:22 AM by salvomic.)
Post: #1
 salvomic Senior Member Posts: 1,396 Joined: Jan 2015
Question about Solve
hi,
an Italian student asked to me what's the best way to solve these equations in Solve:

E1: A*(2*π*10)*COS(P)+11*A*SIN(P) = 0
E2: 11*A*COS(P)-A*(2*π*10)*SIN(P) = 23
where A is amplitude, P phase, the rest 2*PI*frequency (here 10 Hz)

I suggest only to set the Prime in DEG mode (he is to get something like 0.36 and 80°, he said).
I get different values with different invite suggestion for A and P (but they are values MOD 360, I think), however also about 0 and about 99.93 (giving A=0.001); giving for A 2 and for P 0 I get about 0 and about 80 also...
For examples the student got -20350160.0698 whit his tries:
-20350160.0698 MOD 360 is about 280 (about 279.93), that's 360-80...
Whit my values (about -0.36 and 99.93) the equations are consistent but a negative amplitude hasn't a physic sense.

But the guy is searching a general good solution if he doesn't know what invite values to give...
Suggestions?

Salvo

∫aL√0mic (IT9CLU) :: HP Prime 50g 41CX 71b 42s 39s 35s 12C 15C - DM42, DM41X - WP34s Prime Soft. Lib
 « Next Oldest | Next Newest »

 Messages In This Thread Question about Solve - salvomic - 08-25-2015 07:16 AM RE: Question about Solve - ww63 - 08-25-2015, 10:27 AM RE: Question about Solve - salvomic - 08-25-2015, 10:29 AM RE: Question about Solve - roadrunner - 08-25-2015, 12:44 PM RE: Question about Solve - salvomic - 08-25-2015, 12:47 PM RE: Question about Solve - DrD - 08-25-2015, 02:00 PM RE: Question about Solve - salvomic - 08-25-2015, 03:43 PM RE: Question about Solve - DrD - 08-25-2015, 07:50 PM RE: Question about Solve - salvomic - 08-25-2015, 07:52 PM

User(s) browsing this thread: 1 Guest(s)