## ErrorRSolve::dsfun cannot be used as a function

I try to solve a recursive formula and find the explicit representation of a

$$a_0 = 1$$

$$a_{n+1} = 3 \sum\limits_{i=0}^{n} a_i$$

RSolve[{a[n] == 3 Sum[a[i], {i, 0, n }], a[0] == 1}, a[n], n] 

and the output is

RSolve: 2\ a[-1+n] cannot be used as a function. 

## Cannot retrieve Mobile Number in Search API

Hi i tried to create new field called Mobile managed property and mapped it to Mobile,People:Mobile,ows_Mobile crawled property connected to AD

https://siteURI.sharepoint.com/_api/search/query?querytext=%27accountname:%22*firstname.lastname*%22%27&sourceid=%27B09A7990-05EA-4AF9-81EF-EDFAB16C4E31%27&selectProperties=%27PreferredName,Path,WorkEmail,PictureURL,JobTitle,Department,Mobile,WorkEmail,AboutMe,Office,Manager 

However, it returns null. Maybe i am missing something.

## Cannot Create a Panorama

Hoping that someone has an answer, I have tried several times to create a panorama, (with different sets of photos, all raw files), and I always get the following message:

Camera Raw Save Status Status: There was an unknown error.

I have tried saving to different locations, but the same message.

Thanks,

## Cannot move (or delete) Groove Music icon in Windows 10

On my new Windows 10 (v1803) PC there are a bunch of strange pre-installed applications, like Groove Music. These clutter up the Start Menu with no hierarchy, just all on the same level. I’d like to put these icons into a separate folder on the Start Menu.

Searching online I’ve found several articles describing how you can (attempt to) uninstall these Windows Store applications, but nothing about how to move or remove the icon. I’m not (yet!) looking to uninstall the app, just to organise the Start Menu into a more logical heirarchy.

In previous versions of Windows, a user could create a folder called (say) Windows Stuff in the appropriate path. Then you could drag the icons into this folder. After acknowledging the UAC prompt the icon has moved. Great! With these new Windows 10 application, however, I can’t seem to do anything with them.

Things I have tried:

• Navigated to C:\ProgramData\Microsoft\Windows\Start Menu\Programs. No icons or .lnk files for these Windows metro apps are visible.
• Navigated to C:\Users\[ME]\AppData\Roaming\Microsoft\Windows\Start Menu\Programs. Likewise, none of these metro apps appear.
• Used WIN+R and then shell:AppsFolder to actually view installed applications. Here I can see the ZuneMusic application (see below), but I can neither delete, uninstall or move it.

• Tried grabbing the icon directly in the Start Menu and dragging it…but a No Entry symbol appears and the icon cannot be moved or removed.

How do you get control over the Start Menu in Windows 10 (in a similar way to Windows 7 or Windows XP)?

## Ionic cannot emulate ios

The build was successful but I can’t emulate it:

When i want to check the file, the ‘platform/ios/build’ folder doesn’t even exist

I’m using osx Mojave btw

## Cannot find rom for my old prestigio multipad 7.0 ultra duo

I cannot find a supported cyanogenmod or android 5.1 or higher for this tablet (currently on 4.1).. does somebody know a place i can find it or a rom ported from another device? I tried xdadevelopers.. thank you anyway!