In a recent tip, TUAW reader Dr. Drang told us about a bug he found on the iPhone/iPod touch's calculator. According to his research, when you type π × 2 + 5 = into the calculator you get 11.283... (the correct answer). However, when you reverse the Pi and 2, entering 2 × π + 5, the answer given is 7.

This error can be demonstrated by entering Pi (3.141592654) manually, instead of using the Pi button -- you will get the correct answer each time. Therefore, this error only shows up when you use the Pi button.

So, be sure to read up on this bug from the tipsters website before you use the calculator for anything too important.

Update: Reader Vineet writes in the comments to note that he believes this behavior is typical of stack-based calculators and should be considered more of an operator-expectations issue than a true bug. Dr. Drang responds (with a little bit of attitude) to disagree, maintaining that the behavior is a legitimate bug.

Thanks for the tip, Dr. Drang!

It probably wasn't the most consequential update of the day, but we did get one big question answered from the iPhone SDK event in February: why the iPhone's calculator icon got changed from round buttons to square ones. Apple apparently had a lot of requests for a scientific version of the calculator, and so in iPhone 2.0, you'll be able to rotate the calc to landscape mode for a sci calc, including squares and square roots, sin, cos, and tan, factorials, and everything else you use to use the old TI-85 for back in the lab.

As we noted, probably not a huge sales point for people planning to pick up a new iPhone (which, at $199 for the 8gb, is pretty much everybody), but the added functionality will be a nice bonus for those of us require a calculator for every little bit of math that needs doing.

Our lucky friends at Engadget somehow got to play with the iPhone 1.2/2.0 beta (no word on if they'll send it along to Erica anytime soon), and they confirmed a lot of things we'd guessed at previously.

Exchange support works as smoothly as Scott and Mike had hoped, but there's still no two-pane Mail client. The multiple mail message selection works, however, and we finally found out why the Calculator button has changed -- apparently there are a ton of new features in there, including a sideways scientific calcalculator. There are a number of other fun features and improvements as well, although the main event, the App Store, only functions enough to give an error that it can't connect.

June can't come any faster, as far as we're concerned. Bring on the iPhone version 2.0!

OS X's Calculator application is something I basically ignore. Between Spotlight and Terminal's bc, I rarely if ever use it. So it was a pleasant and welcome surprise when TUAW reader Roberto Mateu gave us a heads up that Leopard's calculator was updated with better RPN support.

Calculator has done RPN for some time--if you're still running Tiger, you can see the old version by selecting View > RPN for any of the three calculator types. Under Tiger, the = button changed to Enter and that was about it. Leopard has updated the RPN calculator by adding multi-line entry so you can see your stack as it grows. It's a much nicer way to use RPN and TUAW heartily approves.

Eagle-eyed reader Travis (thanks!) went over Engadget's photos of the O2 iPhone announced yesterday morning, and sussed out every little feature and update he saw on their iPhones that current owners don't have. We can only believe that the iPhones shown must have already been updated to 1.1.1, and that US iPhones, via Software Update, will receive these features soon.

• Now Playing controls everywhere!
• Double clicking the home screen goes to Favorites or iPod, similar to what the iPod touch can do now.
• The iTunes WiFi Store (well duh)
• Closed captioning, and the already leaked support for Video Out.
• New Calculator icon-- to match the iPod touch as well
• International keyboards
• Network setup with VPN support and EDGE disabling
• A "Carrier" menu, but your guess is as good as ours on that one. This could simply be a European thing, as their rules may not match American regulations. I really don't think AT&T would like to see Apple give the ability to unlock iPhones from their service in the next major software update.

Not listed: the disabling of ringtones, and a rollback of all the open source hacks so far. Ha, I'm kidding! Ok, maybe only about 50% kidding. Otherwise, looks like a nice update.

Jonas at the MacThemes Forums got tired of looking at the "...old Cartoonish orangy interface" of Apple's calculator Dashboard widget. So, he made his own. It's a simple black affair with recessed buttons. We think it looks sharp.

When you install it, you'll be asked if you want to replace the existing Calculator widget. Just say "Yes." (of course, you made a backup first, right?).

[Via The Iconfactory]

Just yesterday we posted on the bc command line calculator. Well on the other end of the UI spectrum is Soulver from Acqualia Software. Its authors claim that Soulver is a "plain English" calculator in that you can actually type in certain (in fact very limited) phrases and get answers, as you see above. In general, though, you'll use Soulver as a normal sort of calculator, but with a pleasing, easy to read interface. The expressions to be evaluated go on in the left column and the answers appear in the right, all in a nice clean list. As you can see, you can also open a couple of palettes with conversions and statistics on the entire column. Perhaps ironically, the actual number crunching power under the pretty GUI is the same bc mentioned above. Soulver is not meant to be a particularly sophisticated scientific calculator (though you can define variables, for instance), but rather a kind of "back of the envelope" replacement. It's an unusual concept, but once you get your mind around the idea of it not looking like a stand-alone calculator, I actually think the paradigm works well (and I put my own money where my mouth is on this one).

Soulver is $17.95 and a demo is available.

When my machine was a rickety little 800 MHz iBook, crusted with too many hacks, apps and utilities, I just gave up on Widgets. Dashboard was a system hog on an already dog-slow machine, and I just killed it off.

My MacBook Pro is another story. While I've eschewed the volume of Widgets a true power-user may install, I have my fair share. Of course, until we're able to safely and securely swap our sets of Widgets around, I just keep a certain set loaded. Yes, I've tried MultiDash, primarily to swap around when I plug in to my 24" external monitor. I would have included a link to the MultiDash page, but going there today either crashed Firefox or made Safari eat up processor. Gotta love that...Anyway, as a Widget, it was too wonky for production use, so here's what I've settled on for daily use:

• Apple's own calendar, weather, iTunes, calculator, and search Widgets (Dictionary, White Pages, Yellow Pages, and Address Book). The unit converter is tucked behind the sticky note
• Google search-- pretty much never use it since Google is built-in to every browser but Flock, although sometimes I use the Blogger one too
  
• Radar-in-Motion-- massive kudos to the poor developer who makes this, as NOAA keeps changing the protocols, formats, etc. I love this thing, but I love weather.
• WeatherBug-- this one has a bunch more features, but ironically doesn't work as well as R-i-M
• iClipLite-- what would I do without this? Very handy for storing form letters, the very ones I use every day
• iStat nano-- surely everyone is using this or its older sibling by now, right? Often I use it to check my IP address, but I really wish I could have it quit bugging me about updates, that is really annoying
• Slothcam-- I have it always tuned to the TGIFriday's camera in Times Square, great for people-watching! (You will see me on there once in a while too)
• Web Translator widget (uses Google)-- handy for quick language lookups, as my Spanish vocab stinks sometimes
• Airport Radar-- handy for checking signal strength
• PackageTracker-- from Monkey Labs, where they make a terrible TV Tracker... only terrible because every week they want me to update it, but it never gets faster or better, yet PackageTracker never bugs me about it
• iCalEvents-- super-fantastic for glancing at my hard schedule for the day
• Backpack widget-- from Chipt.com, this Widget has saved me so many times it is scary. If you are a serious GTD nut, you must have a Backpack widget for simple ticklers, and this does the job better than almost anything. Plus, I can access my Backpack reminders from anywhere via web, so I have a constant backup. Combined with floating reminders via Growl, and you can really tame your to-do list.
  
• an obligatory digg widget-- because I'm addicted, I'll admit (where's that Netscape widget?)
• Veronica Belmont-- she's not a Widget, but a spunky tech pundit for CNet
• and of course, I have a TUAW widget!

So what's in your Dashboard?

Remember that iPod storage calculator iLounge released? It seems Christian Chladek, maker of such other widgets as the Morse Code Translator, was inspired to provide an iPod calculator in widget form. iPodage allows you to pick your iPod model and adjust all the vital settings to do some quick and dirty math on just how many tunes you can cram into your pocket for the road. For bonus points, the widget can even shrink out of your way should you need to reclaim some Dashboard space.

iPodage is donationware and available from Christian's site.

Apple offers their own advertising-friendly estimation of how many songs each model of iPod can hold, but those numbers are based on fairly unrealistic standards of 128Kbps AAC songs that are a mere 4 minutes long. Toss in a few tracks from Phish or Beethoven's 5th, and you can easily hurl this song estimation into the realm of 'anyone's guess.'

Enter iLounge's iPod Storage Calculator, a handy little web tool (what, no widget?) that lets everyone from newbies to demanding audiophiles perform some quick calculations to figure out just how many songs, even at varying bitrates, their iPod can hold.
As a matter of fact, the only thing about this calculator that makes it iPod-specific is the handy pull-down menu offering one-click access to every storage capacity the iPod has ever packed; in other words - anyone can use this tool to get an idea of how many songs they can bring along.

Thanks Josh