Flipping between landscape and portrait mode on the iPhone can be useful, or it can be detrimental to getting things done. Locking the screen orientation in iOS is a simple proposition, however there are some apps where one mode is almost always better than the other. So why not automatically switch when needed?
Using the stock iOS calculator in landscape mode provides many scientific functions beyond the extremely simple portrait mode numerical calculator. If you're interested in only using the scientific calculator the tweak LandscapeCalc will automatically switch the calculator app into this mode. Once installed on a jailbroken iOS device, there are no settings to configure.
LandscapeCalc takes after a similar tweak that automatically plays all videos in landscape mode, to take advantage of the widescreen aspect ratio. Like LandscapeCalc, the tweak LandscapeVideos is free to install from Cydia, and it makes sure that videos are always played in the landscape orientation. LandscapeCalc probably has a narrow audience, however those who use the iOS scientific calculator often will find it useful.
LandscapeCalc is available on Cydia from the BigBoss repo free of charge. Check here for instructions on how to jailbreak iOS 6.x with evasi0n. You can also find out how to purchase and install Cydia tweaks with this guide.