In each of 14 through 20: a. Find an equation of the form H( x, y) = c satisfied by the trajectories. G b. Plot several level curves of the function H. These are trajectories of the given system. Indicate the direction of motion on each trajectory.dx/dt = y, dy/dt = sin x (undamped pendulum) 2

MAC 1114 Analytic Trigonometry 2/2/16 notes 8. Rewrite an equivalent expression (HINT: use reference angles) 2 a) tan (7pi/9) Step 1: Draw/ locate angle Step 2: Determine if trig ratio is negative or positive In this case tan is going to be negative, because 7pi/9 falls in quadrant 2, where only Sin is positive.