Post Reply 
Differences between the different solve/zeros commands?
10-23-2014, 11:36 PM
Post: #1
Differences between the different solve/zeros commands?
What are the differences between the different solve/zeros commands and which commands are recommended when?

Trying to solve this for x but cant find a working command:

ARG((-e^(-0.3*i*x))/(x^2-i*x))=-165

Any help would be really appreciated!
Find all posts by this user
Quote this message in a reply
10-24-2014, 01:05 AM
Post: #2
RE: Differences between the different solve/zeros commands?
(10-23-2014 11:36 PM)pr0 Wrote:  What are the differences between the different solve/zeros commands and which commands are recommended when?

Trying to solve this for x but cant find a working command:

ARG((-e^(-0.3*i*x))/(x^2-i*x))=-165

Any help would be really appreciated!

What calculator?
Find all posts by this user
Quote this message in a reply
10-24-2014, 06:18 AM
Post: #3
RE: Differences between the different solve/zeros commands?
(10-24-2014 01:05 AM)Don Shepherd Wrote:  ...
What calculator?

Since this forum is named "HP Prime", the HP Prime?
Find all posts by this user
Quote this message in a reply
10-24-2014, 08:04 AM
Post: #4
RE: Differences between the different solve/zeros commands?
This equation has no solution. If you take exp(0.3*i*x), x must be in radians, therefore argument should be rescaled in -pi..pi.
fsolve(arg((-e^(-0.3*i*x))/(x^2-i*x))=-165*pi/180,x=-10..10)
returns 2 solutions.
Find all posts by this user
Quote this message in a reply
10-25-2014, 10:01 PM
Post: #5
RE: Differences between the different solve/zeros commands?
(10-24-2014 08:04 AM)parisse Wrote:  This equation has no solution. If you take exp(0.3*i*x), x must be in radians, therefore argument should be rescaled in -pi..pi.
fsolve(arg((-e^(-0.3*i*x))/(x^2-i*x))=-165*pi/180,x=-10..10)
returns 2 solutions.

Thanks! When is fsolve recommended and when is other commands recommended for solving? Any other cases radians must be selected?
Find all posts by this user
Quote this message in a reply
10-26-2014, 07:34 AM
Post: #6
RE: Differences between the different solve/zeros commands?
fsolve is recommended if you want a numeric answer, solve if you want a symbolic answer (but solve can only find roots for polynomial-like equations).
Find all posts by this user
Quote this message in a reply
Post Reply 




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