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Trigonometry

Course: Trigonometry > Unit 2

Lesson 5: Trigonometric values on the unit circle
Math
Trigonometry
Trigonometric functions
Trigonometric values on the unit circle
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Trig identities from reflections and rotations

CCSS.Math: HSF.TF.A.3
Google Classroom

Problem

On the following unit circle, theta is in radians.
A unit circle with an angle from the positive x-axis to a ray labeled theta. The point where the ray intersects the circle is labeled negative 0.42, 0.91 and is in the second quadrant.
Without a calculator, evaluate the following expressions to the nearest hundredth.
ExpressionValue
cosine, left parenthesis, pi, minus, theta, right parenthesis
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
cosine, left parenthesis, 2, pi, plus, theta, right parenthesis
  • Your answer should be
  • an integer, like 6
  • a simplified proper fraction, like 3, slash, 5
  • a simplified improper fraction, like 7, slash, 4
  • a mixed number, like 1, space, 3, slash, 4
  • an exact decimal, like 0, point, 75
  • a multiple of pi, like 12, space, start text, p, i, end text or 2, slash, 3, space, start text, p, i, end text
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