How to do cube root on a normal calculator?

So, I'm doing Geometry homework, and it involves having to do cube root. In class, the graphing calculators will do it, but I can't for the life of me find a calculator online that will give me cube root, and the one on my iphone doesn't do it either. How do I get the cube root?

Can I make Siri sound like Jarvis?

I want to get Siri to sound like Jarvis but I don't want to have to jailbreak my iphone. There's a YouTube video out only for jailbroken iphones

How to get rid of Cydia jailbreak without PC or iTunes?

I recently Jailbroke my iPhone 4s with iOS 6.1.2. I would like to get rid of the Jailbreak now. One problem.something on Cydia made it to where my phone can only charge while powered off. Almost as if to prevent me from restoring it. I have tried several deifferent cords, different wall chargers, and even different computers. When I press "Erase all content and settings" it just loads forever.but, it will charge during the infinite loading loop, meaning that this is indeed a software issue and not a hardware issue.So, here it is: How do I get rid of this jailbreak if it prevents me from updating my phone, syncing my phone, and even charging my phone while on?

Please only respond if you know what you are talking about.

How to learn more about astronomy?

The other day I downloaded an app on my IPhone that let's me see the names of stars and planets I point it at. I climbed onto my roof and started looking through it and it was the coolest thing I have ever seen. I loved it so much that every night I have gone up and looked at them. Now, I want to learn as much as I can about astronomy. Can someone please tell me how I can do this? Like what do I need to know? I honestly think its my new passion, so I want to study up on it but I have no clue what to study. Can you help me?!

What app do you use to make split-pics?

Alright so some of my friends have been posting pictures on Facebook and instagram where it looks like there's two of them doing a different pose in the picture. You can't tell that it's only one person, and it's not just flipped around. I understand it is a split-pic, but would somebody mind telling me what app I could make one of these pictures with? (For iPhone)