Other techniques may be used to find ( exact ) phase portraits and approximate periods .
A very useful qualitative picture of the pendulum 's dynamics may be obtained by piecing together such linearizations , as seen in the figure at right .
Other techniques may be used to find ( exact ) phase portraits and approximate periods .
A very useful qualitative picture of the pendulum 's dynamics may be obtained by piecing together such linearizations , as seen in the figure at right .