Here is the Figure:
http://upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Coupled_Harmonic_Oscillator.svg/300px-Coupled_Harmonic_Oscillator.svg.png
So How do you sketch displacements of +1 units for both masses to represent one natural mode and sketch displacements -1 and +1 (left and right masses, respectively) ?
Then how do you:
Sketch the system for displacements +2 and +4, representing a string being plucked nearer one end than the other. Show three units of one natural mode mixed with one unit of the other can make this shape and therefore would be the recipe for the plucked vibration.
http://upload.wikimedia.org/wikipedia/commons/thumb/3/3f/Coupled_Harmonic_Oscillator.svg/300px-Coupled_Harmonic_Oscillator.svg.png
So How do you sketch displacements of +1 units for both masses to represent one natural mode and sketch displacements -1 and +1 (left and right masses, respectively) ?
Then how do you:
Sketch the system for displacements +2 and +4, representing a string being plucked nearer one end than the other. Show three units of one natural mode mixed with one unit of the other can make this shape and therefore would be the recipe for the plucked vibration.