ELECTRONIC SPREADSHEATS Chapter 14_Part2

Dr. Bahaa Al-Sheikh & Eng. Mohammed AlSumady

Intoduction to EngineeringBME152

Matrix Algebra

Example 14.8 :

Example 14.8

1. In the cells shown, type the appropriate characters and values. Use the Format Cells and Font option to create the boldface variables, as shown above.

Example 14.8

2. In cell A10, type [A] +[B] =, and using the left mouse button, pick cells B9 through D11, as shown in the figure

Example 14.8

3. Next, in the Formula bar, type =B3:D5 G3:I5 and, while holding down the Ctrl and the Shift keys, press the Enter key. Note that using the mouse, you could also pick the ranges of B3:D5 or G3:I5 instead of typing them. This sequence of operations will create the result shown. You follow a procedure similar to the one outlined in step 2 to perform [A] -[B] , except in the Formula bar type =B3:D5-G3:I5.

Example 14.8

4. To carry out the matrix multiplication, first type [A][B] = in cell A18, as shown. Then pick cells B17 through D19.

Example 14.8

5. In the Formula bar, type =MMULT (B3:D5,G3:I5), and, while holding down the Ctrl and the Shift keys, press the Enter key. Similarly, you can perform the matrix operation [A]{C }. First you pick cells B21 through B23, in the Formula bar, type =MMULT(B3:D5, L3:L5), and, while holding down the Ctrl and the Shift keys, press the Enter key. This sequence of operations will create the result shown in the figure.

Curve Fitting with Excel

Curve fitting deals with finding an equation that best fits a set of data

The purpose of this section is to demonstrate how to use Excel to find an equation that best fits a set of data which you have plotted.

Example 14.10

Recall, the spring constant k is determined by calculating the slope of a force–deflection line (i.e., slope =change in force /change in deflection).Excel was used to plot the deflection– load results of the experiment using the XY (Scatter) without the data points connected, as shown in the Figure 14.13

Example 14.10

To add the trendline or the best fit, with the mouse pointer over a data point, click the right button and choose Add Trendline .

Next, from the Format Trendline dialog box, under Trend/Regression type, select Linear, and toggle on the Set intercept = and the Display equation on chart, as shown in Figure 14.15.

Example 14.10

After you press close, you should see the equation y=0.5542x on the chart, as shown in Figure 14.16. We have edited the variables of the equation to reflect the experimental variables as shown in Figure 14.17.

Example 14.10

Example 14.11

Find the equation that best fits the following set of data points in Table 14.10.

Do at home and if you have question ,ask.

Summary

You should know that a spreadsheet is a tool that can be used to solve an engineering problem. Spreadsheets are commonly used to record, organize, and analyze data using formulas.

You can input your own formulas or use the built-in functions provided by the spreadsheet.

should also know how to edit the content of a cell.

You should know how to select multiple cells and create a range.

Summary

You should understand how to refer to a cell by its address.

You should be familiar with Excel’s built-in functions.

You should know how to create a proper engineering chart using Excel.

You should know how to perform matrix operations with Excel.

You should know how to perform curve fitting with Excel.