exercise 9: switch annotation call to match with rest of the annotati…

…ons.

The text annotations for cos and sin are now in the same code block as the
corresponding scatter-dot and the dashed line.

scripts/exercice_9.py

@@ -32,17 +32,17 @@
 plt.plot([t,t],[0,np.cos(t)],
          color ='blue',  linewidth=1.5, linestyle="--")
 plt.scatter([t,],[np.cos(t),], 50, color ='blue')
-plt.annotate(r'$\sin(\frac{2\pi}{3})=\frac{\sqrt{3}}{2}$',
-             xy=(t, np.sin(t)),  xycoords='data',
-             xytext=(+10, +30), textcoords='offset points', fontsize=16,
+plt.annotate(r'$\cos(\frac{2\pi}{3})=-\frac{1}{2}$',
+             xy=(t, np.cos(t)),  xycoords='data',
+             xytext=(-90, -50), textcoords='offset points', fontsize=16,
              arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2"))
 
 plt.plot([t,t],[0,np.sin(t)],
          color ='red',  linewidth=1.5, linestyle="--")
 plt.scatter([t,],[np.sin(t),], 50, color ='red')
-plt.annotate(r'$\cos(\frac{2\pi}{3})=-\frac{1}{2}$',
-             xy=(t, np.cos(t)),  xycoords='data',
-             xytext=(-90, -50), textcoords='offset points', fontsize=16,
+plt.annotate(r'$\sin(\frac{2\pi}{3})=\frac{\sqrt{3}}{2}$',
+             xy=(t, np.sin(t)),  xycoords='data',
+             xytext=(+10, +30), textcoords='offset points', fontsize=16,
              arrowprops=dict(arrowstyle="->", connectionstyle="arc3,rad=.2"))
 
 plt.legend(loc='upper left', frameon=False)