Simultaneous Equations
Simultaneous Equations
Simultaneous Equations
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MET 107<br />
Homework 21 – <strong>Simultaneous</strong> <strong>Equations</strong><br />
Later in this document, you will be asked to solve a series of simultaneous equations. Pay attention to the<br />
instructions for producing documentation using the Grid and Header and Cell Formulas macros.<br />
Solve each of the systems of equations using matrix math functions in Excel. Whenever a variable is missing<br />
from an equation, its coefficient will be zero in the coefficient matrix. Each problem should be checked by<br />
multiplying the coefficient matrix by the solution matrix to obtain the original constant matrix.<br />
The following is an example (do not turn this in):<br />
.5x 1 - .4x 2 + 3x 4 = 5.2<br />
.8x 1 - 3x 2 + x 3 - .5x 4 = -6.2<br />
x 1 + .4x 2 - .2x 3 + .6x 4 = 4.1<br />
.2x 1 + .6x 2 - .3x 3 = 7.0<br />
Note: Your input region should<br />
list the equations as shown.<br />
You do not have to include the<br />
text boxes.<br />
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Solve the following equations:<br />
A) 2x 1 + 3x 2 = -10<br />
3x 1 - 2x 2 = -2<br />
B) 4x 1 – x 2 – 3x 3 = 1<br />
2x 1 + x 2 + 2x 3 = 5<br />
8x 1 + x 2 - x 3 = 5<br />
Note that A) and B) are to be done on a single worksheet.<br />
Print this worksheet using the both the Grid and Header and the Copy Cell Formula macro.<br />
C) 2x 1 – 3x 2 + x 3 – 2x 4 = 8<br />
x 1 – x 2 - 6x 4 = -4<br />
3x 2 + 4x 4 = 6<br />
6x 1 + 2x 2 – 3x 3 + 7x 4 = 12<br />
Note that C) is to be done on a single worksheet.<br />
Print this worksheet using the both the Grid and Header and the Copy Cell Formula macro.<br />
D) This problem involves solving 10 equations for 10 unknown forces in order to determine the forces in<br />
truss members. F 1 , F 2 , 1 , and 2 should be set up to be variable inputs in your sheet.<br />
Start a new worksheet for this problem.<br />
The equations of equilibrium are as follows:<br />
R 1 + T 1 cos 60° + T 2 = 0<br />
R 2 + T 1 sin 60° = 0<br />
-T 2 – T 3 cos 60° + T 4 cos 60° + T 5 = 0<br />
T 3 sin 60° + T 4 sin 60° = 0<br />
-T 5 – T 6 cos 60° = 0<br />
T 6 sin 60° + R 3 = 0<br />
Hint:<br />
The easiest way of displaying these<br />
equations in Excel would be to use the<br />
Snipping Tool to insert an image of<br />
these.<br />
-T 1 cos 60° + T 3 cos 60° + T 7 – F 1 cos 1 = 0<br />
-T 1 sin 60° – T 3 sin 60° – F 1 sin 1 = The information in these boxes are your<br />
“constants” and are a function of the Inputs<br />
-T 4 cos 60° – T 7 + T 6 cos 60° – F 2 cos 2 = 0<br />
-T 4 sin 60° – T 6 sin 60° – F 2 sin 2 = 0<br />
Note that R 1 is the horizontal reactive force, R 2 is the vertical reactive force at the left support and R 3 is the<br />
vertical reactive force at the right support.<br />
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In Excel, solve the system of equations.<br />
Use a format similar to the one shown below for your calculations.<br />
Draw a figure of the truss and include textboxes to label the figure. Link the textboxes to the results so the<br />
force in each member (T 1 – T 7 ; shown in the boxes) and the reactions (R 1 – R 3 ) are shown in the figure. The<br />
given forces and their angles should also appear in the figure, linked to the input boxes. The solution to the<br />
given problem is shown.<br />
<br />
Print your worksheet for the above test case using the both the Grid and Header and the Copy Cell<br />
Formula macro.<br />
Change the input values as follows:<br />
F 1 = 6000 lbs, 1 = 60 deg, F 2 = 2000 lbs, 2 = 90 deg.<br />
<br />
Print your worksheet using the both the Grid and Header macro only.<br />
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