To understand why the formula `=(D2 + B2 C2)` would produce an error message, let's first analyze the context and the details given in the spreadsheet and the formula.
### Breakdown of the Spreadsheet Setup
The spreadsheet is designed to calculate the value of [tex]\( v \)[/tex] based on the formula:
[tex]\[ v = u + at \][/tex]
Where:
- [tex]\( u \)[/tex] is the initial velocity,
- [tex]\( a \)[/tex] is the acceleration,
- [tex]\( t \)[/tex] is the time.
### Understanding the Cell References
In the provided spreadsheet:
- Column B contains values of [tex]\( u \)[/tex] (initial velocity).
- Column C contains values of [tex]\( a \)[/tex] (acceleration).
- Column D contains values of [tex]\( t \)[/tex] (time).
### Components of the Provided Formula
The incorrect formula typed in by the student is `=(D2 + B2 C2)`. Breaking this down, we get:
- `D2` refers to the cell in the same row under Column D.
- `B2` refers to the cell in the same row under Column B, which contains the value of [tex]\( u \)[/tex].
- `C2` refers to the cell in the same row under Column C, which contains the value of [tex]\( a \)[/tex].
### Evaluating the Formula
If we look at D2 specifically:
- In cell D2 (Column D, Row 2), it is essentially referencing itself when we include `D2` in the formula.
This means the formula `=(D2 + B2 * C2)` is trying to compute:
[tex]\[ \text{D2} = \text{D2} + (\text{B2} \times \text{C2}) \][/tex]
This creates a circular reference because the result cell (D2) is trying to calculate based on its own value (D2).
### Proper Formula for Calculation
What the student intended to achieve is to calculate the value of [tex]\( v \)[/tex] using [tex]\( u \)[/tex], [tex]\( a \)[/tex], and [tex]\( t \)[/tex]. The correct cell references for these are:
- [tex]\( u \)[/tex] is in B2,
- [tex]\( a \)[/tex] is in C2,
- [tex]\( t \)[/tex] is in D2.
The correct formula should be structured as:
[tex]\[ \text{result in E2} = B2 + (D2 \times C2) \][/tex]
So, in Excel it should be in cell E2:
[tex]\[ = B2 + C2 \times D2 \][/tex]
### Conclusion
The error occurred because the student mistakenly referenced the cell D2 itself within its own calculation, leading to a circular reference error. The correct formula should reference values of [tex]\( u \)[/tex], [tex]\( a \)[/tex], and [tex]\( t \)[/tex] properly and compute it in the appropriate result cell.
