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Defining the Unit Circle quiz #1 Flashcards

Defining the Unit Circle quiz #1
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  • How can you determine if a given point (x, y) is on the unit circle?
    To determine if a point (x, y) is on the unit circle, substitute its coordinates into the equation x² + y² = 1. If the equation is true, the point lies on the unit circle.
  • What is the center of the unit circle on a coordinate plane?
    The center of the unit circle is at the origin, which is the point (0, 0). This means both the x and y coordinates of the center are zero.
  • How are angle measures typically started and measured on the unit circle?
    Angle measures on the unit circle start from the positive x-axis at 0 degrees. They are measured counterclockwise around the circle.
  • What is the radian measure for a full rotation around the unit circle?
    A full rotation around the unit circle is 2π radians. This is equivalent to 360 degrees.
  • Which ordered pair corresponds to 90 degrees on the unit circle?
    The ordered pair for 90 degrees is (0, 1). This point is at the top of the unit circle.
  • What is the equation of the unit circle and what does each variable represent?
    The equation of the unit circle is x² + y² = 1. Here, x and y represent the coordinates of any point on the circle.
  • If a point has coordinates (a, b), what must be true for it to lie on the unit circle?
    The point (a, b) must satisfy the equation a² + b² = 1. If this equation holds, the point is on the unit circle.
  • What is the x-coordinate of the point on the unit circle at 180 degrees?
    At 180 degrees, the x-coordinate is -1. The corresponding point is (-1, 0).
  • How do you find the y-coordinate for a point on the unit circle at 270 degrees?
    At 270 degrees, the y-coordinate is -1. The point at this angle is (0, -1).
  • What angle in degrees corresponds to the point (1/2, √3/2) on the unit circle?
    The point (1/2, √3/2) corresponds to 60 degrees on the unit circle. This is a standard reference angle.