If the orbit of the comet is approximated by the equation , how far is it from the sun at the vertex of the orbit? Distances are measured in astronomical units (AU).
A) 2 AU
B) 4 AU
C) 1 AU
D) 5 AU
E) 3 AU

Question

If the orbit of the comet is approximated by the equation  , how far is it from the sun at the vertex of the orbit? Distances are measured in astronomical units (AU). 
A) 2 AU 
B) 4 AU 
C) 1 AU 
D) 5 AU 
E) 3 AU

Quizplus · Accepted Answer

The vertex of the orbit is the point at which the comet is closest to the sun, also known as perihelion. At this point, the distance from the sun is equal to the semi-major axis of the ellipse, which is given by the coefficient in front of the "cos" term in the equation. In this case, the coefficient is 1, so the distance from the sun at perihelion is 1 AU.

If the Orbit of the Comet Is Approximated by the Equation