Microsoft Office Tutorials and References

In Depth Information

**Rounding Numbers**

4.
Use an array formula to calculate the inverse of the coefficient matrix. In Figure 10-3, the

following array formula is entered into the range I6:J7. (Remember to press

Ctrl+Shift+Enter to enter an array formula.)

{=MINVERSE(I2:J3)}

5.
Use an array formula to multiply the inverse of the coefficient matrix by the constant

matrix. In Figure 10-3, the following array formula is entered into the range J10:J11. This

range holds the solution.

{=MMULT(I6:J7,L2:L3)}

Refer to Chapter 14 for more information on array formulas. Chapter 16 demonstrates

how to use iteration to solve some simultaneous equations.

Figure 10-3:
Using formulas to solve simultaneous equations.

You can access the workbook,
simultaneous equations.xlsx
shown in Figure
,

10-3, on the companion CD-ROM. This workbook solves simultaneous equations with

two or three variables.

Rounding Numbers

Excel provides quite a few functions that round values in various ways. Table 10-1 summarizes

these functions.

Itâ€™s important to understand the difference between rounding a value and formatting a

value. When you format a number to display a specific number of decimal places,

formulas that refer to that number use the actual value, which may differ from the

displayed value. When you round a number, formulas that refer to that value use the

rounded number.