EGR 103/Fall 2017/Minilab 7

Typos

Prior to 6:45am on 12/5/2017, these problems used numbers from a previous edition of the book. This particularly changed the answers to 7.8.3 and 7.8.4. Those have been updated.

7.8.1

Be sure to store your data using code similar to a = np.array([1, 2, 3, 4]) and not just a = [1, 2, 3, 4].

Also, to return the result of a long formula, be sure to put the whole thing in parentheses to break it across lines; for instance:

return (1 + 2 + 3 + 
     4 + 5 + 6 + 7)

For the legend, add labels to each plot command and then call the legend command; for example:

plt.plot(t, x, 'k-', label='position')
plt.plot(t, v, 'r--', label='velocity')
plt.legend()

St: 5.793e+00
Sr: 7.850e-02
r2: 9.864e-01

The model should be a green dashed line going through the data points.

7.8.2

Root 1: 2.338e+00
Root 2: 7.762e+00
Min of y=-2.086e+01 at x=+1.279e+00
Min of y=-3.274e+01 at x=+8.708e+00
Min of y=-2.086e+01 at x=+1.279e+00
Max of y=+1.953e+02 at x=+5.702e+00

The graph should be like your graph for Lab 5

7.8.3

(1)
[[ 5  8 15]
 [ 8  4 10]
 [ 6  0 10]]
(3)
[[ 3 -2 -1]
 [-6  0  4]
 [-2  0 -2]]
(4)
[[28 21 49]
 [ 7 14 49]
 [14  0 28]]
(5)
[[3 6 1]]
(6)
[[25 13 74]
 [36 25 75]
 [28 12 52]]
(7)
[[54 76]
 [41 53]
 [28 38]]
(8)
[[ 9  2]
 [ 4 -1]
 [ 3  7]
 [-6  5]]
(11)
[[ 66  19  53]
 [ 19  29  46]
 [ 53  46 109]]
(12)
[[46]]

7.8.4

8.3:
[[-15.18115942]
 [ -7.24637681]
 [ -0.14492754]]
8.5:
[[-0.53333333+1.4j       ]
 [ 1.60000000-0.53333333j]]

7.8.5

Note: when you define your function for curve fitting, the independent variable needs to be the first argument, followed by any constants you are trying to find. Your definition line will likely be something like:

def func(i, p_max, i_sat):

St: 2.327e+04
Sr: 1.116e+03
r2: 9.520e-01

Coefficients and graph should match your for this lab. Be sure you are using good initial guesses - bad initial guesses will result in a flat red line!