Trigonometry
Splendid Simulation of a HP-28S
The developer has been implementing most HP28s functions, and the few that are still missing don’t hurt too much (e.g. the ALGEBRA menu, but for this one might be better of with a dedicated CAS system anyway). Only drawback is its name - no one would guess to find a full-fledged HP28 simulator behind something called Halcyon, and also the icon does not hint at its true origins.
So in brief this is highly recommended to any HP enthusiast. The original HP28 layout with the separate alphanumeric keypad makes it very easy to use. It runs natively and makes full use of the iOs graphics display and resolution to its advantage (gestures, copy, paste, scrolling etc).
I had the hp28s. This is a good replica
Cons: free version is too locked down to tell how well it works. I would have like to tried out other features, but that requires at least 1 upgrade possibly more. I could not tell for sure. I would pass on this one since I cannot tell how well it will work.
Response from developer
I appreciate the feedback and I am sorry you found the free version locked down. But I am wondering if perhaps there is a different problem. The free version is fully featured and I believe is quite functional without purchasing extra features. There are in-app purchases which unlock the following: - A larger display which also removes in-app advertisement banners - Unit conversion so you can convert feet to meters or any number of other units, including units you define yourself. - Programming support so you can create your own custom actions and operations. - The ability to create directories to store your own symbols in a hierarchical tree. Those are the only restrictions in the free version. You can do basic calculations with real numbers, integers, complex numbers, vectors and matrices. You can enter equations, plot them, perform calculus on them, evaluate them for various values of variables. Perhaps you were having a technical issue with the app which was preventing it from working for you and I am more than happy to work with you on that and help you to resolve it.
