Final answer:
The trajectory of a projectile can be described by a parabola with the equation y = ax + bx². This equation can be obtained by solving equations for x and y positions and substituting them into each other.
Step-by-step explanation:
The trajectory of a projectile can be described by the equation y = ax + bx², which is in the form of a parabola. To obtain this expression, we can solve the equation x = Voxt and substitute it into the expression for y = Voyt - (1/2)gt², where Vox is the initial velocity in the x-direction, Voy is the initial velocity in the y-direction, g is the acceleration due to gravity, and t is the time. By solving for t in the x equation and substituting it into the y equation, we obtain the equation of a parabola in vertex form.