Trigonometry

• tan 45˚ 1
• cos 45˚ √2/2
• sin 45˚ √2/2
• tan 60˚ √3
• tan 30˚ √3/3
• cos 60˚ 1/2
• cos 30˚ √3/2
• sin 60˚ √3/2
• sin 30˚ 1/2
• Negative angles rotate clockwise
• Positive angles

  Rotate counterclockwise
• Terminal side (ray)


  the other ray, where the angle "ends"
• Initial side (ray)


  the ray on the x-axis
• Standard position

  An angle is in standard position on the coordinate plane if its vertex is of the origin and the ray is on the positive x-axis
• Trigonometric angle

  Formed by rotating a ray about its endpoint
• Reference angles

  The acute angles determined by the terminal side of theta and the x-axis (angle formed)
• Quadrantal angles


  Angles in standard position where the terminal side lies on the x or y-axis (multiples of 90)
• What is the radian measure of a full circle?

  2π
• What is the radian measure of a semicircle?

  π
• Radian

  Unit of an angle at the center of a circle whose arc is equal in length to the radius