Troubleshooting - A Guide to MATLAB for Beginners and Experienced Users - page 246

[ -4*lambertw(1/4*log(2))/log(2)]
[ -4*lambertw(1/4*i*log(2))/log(2)]

Infactwegetthethreerealsolutionsalreadyfoundandtwocomplexsolutions.

double(symroots)

ans =
1.2396
16.0000
-0.1609 + 0.9591i
-0.8613
-0.1609 - 0.9591i

Only the real solutions correspond to points where the graphs intersect.

Practice Set B

Problem 1

(a)

[X, Y] = meshgrid(-1:0.1:1, -1:0.1:1); contour(X, Y, 3*Y +
Y.ˆ3 - X.ˆ3, 'k')

1

0.8

0.6

0.4

0.2

0

− 0.2

− 0.4

− 0.6

− 0.8

− 1

− 1 − 0.8 − 0.6 − 0.4 − 0.2 0 0.2 0.4 0.6 0.8 1

[X, Y] = meshgrid(-10:0.1:10, -10:0.1:10); contour(X, Y, 3*Y
+ Y.ˆ3 - X.ˆ3, 'k')