The step response of second-order oscillator systems is given by the following equation:

where is the time, (Greek letter "xi") is the damping ratio, and (Greek letter "omega") is the undamped natural frequency.

The following figure is a 2-by-1 subplot. The top subplot contains a plot of against for various values. The bottom subplot contains a plot of  against for a single value of  and the maximum value is marked.

Write the Python code to reproduce the figure, using the following information:

• Any required packages must be imported
• A lambda function must be used to define y
• = 10.26
• is a 1D array from 0 to 1 (inclusive) with 200 points
• The line colour specifications are Python's default and do not need to be explicitly stated
• The titles and axes are labelled accordingly
• The figure layout is constrained

• Top subplot:

  • = 0.2, 0.4, 0.6, 0.8

  • The legend should not be hardcoded and is positioned in the best location
  • A loop should be used

• Bottom subplot:

  • = 0.65
  • The maximum point is marked with a red diamond
  • The grid is turned on
  • The legend should not be hardcoded and is positioned in the lower right corner

Copy and paste your Python code in the plain text box below.