Code cells may depend on previous code cells. If a previous code cell has not been executed before, your current cell may lack required data. Try re-running all previous code cells in their given order
If you modified the code cell, look for hints at the end of the error message.
That may happen if you left the system idle for too long.
Your calculations run on a free virtual server provided by sageCell.sagemath.org. Depending on the load of the underlying server cluster, your server may be deleted if it is idle for too long. When you evaluate a cell after that, a new server is set up for you and you have to redo all required code cell executions.
The text analyzes a specific balloon flight which is loaded when the variable randomBalloon in the first cell has its default value of False. The text does not change when you change any code cell, for instance to load another flight.
In the web version, the Read button in the main menu shows the unchanged default version and you can reset all cells by reloading the page,
If you see a blue header, click on the Execute button in this header.
If, instead, you see a green button Open with one click, click on it to save your own copy as a Jupyter notebook in CoCalc. Note: You may have to create a paid CoCalc account to run notebooks with internet access.
Enlarge your window, use the scrollbars of the code cell or copy the code from the cell to another editor. Scrollbars may only appear after you click into the cell and move your mouse!
If you didn't change the code, you can see the full code in the web version when you select Read in the header menu.
Walk on safe ground! If you can answer the questions, you know you are ready to proceed. Even if you cannot, many questions have a Written Example that explains, how a similar problem is solved and what is the mathematical background.
You will notice, that the solution you provided for a linked question is used implemented in the next code cell. Thus, understanding the solution will help you to understand the code and to adapt it at will.
No, the questions provide similar problems.
It may be hidden behind the graphic formula editor; click anywhere eles to hide the editor.
If the question text is very long, you may need to scroll down.