Math Problem Statement

The figure shows an angle θ in standard position with its terminal side intersecting the unit circle. Evaluate the six circular function values of θ.

Solution

To evaluate the six trigonometric function values for angle θ\theta based on the given diagram, we need to use the coordinates provided for the point on the unit circle where the terminal side of θ\theta intersects.

The coordinates of the point are: (22,22)\left(-\frac{\sqrt{2}}{2}, \frac{\sqrt{2}}{2}\right) These coordinates represent the (x,y)(x, y) values on the unit circle for angle θ\theta, where:

  • x=22x = -\frac{\sqrt{2}}{2}
  • y=22y = \frac{\sqrt{2}}{2}

Given that the radius rr of the unit circle is 1, we can now calculate each of the six trigonometric functions:

  1. Sine (sinθ\sin \theta): sinθ=y=22\sin \theta = y = \frac{\sqrt{2}}{2}

  2. Cosine (cosθ\cos \theta): cosθ=x=22\cos \theta = x = -\frac{\sqrt{2}}{2}

  3. Tangent (tanθ\tan \theta): tanθ=yx=2222=1\tan \theta = \frac{y}{x} = \frac{\frac{\sqrt{2}}{2}}{-\frac{\sqrt{2}}{2}} = -1

  4. Cosecant (cscθ\csc \theta): cscθ=1sinθ=122=2\csc \theta = \frac{1}{\sin \theta} = \frac{1}{\frac{\sqrt{2}}{2}} = \sqrt{2}

  5. Secant (secθ\sec \theta): secθ=1cosθ=122=2\sec \theta = \frac{1}{\cos \theta} = \frac{1}{-\frac{\sqrt{2}}{2}} = -\sqrt{2}

  6. Cotangent (cotθ\cot \theta): cotθ=cosθsinθ=2222=1\cot \theta = \frac{\cos \theta}{\sin \theta} = \frac{-\frac{\sqrt{2}}{2}}{\frac{\sqrt{2}}{2}} = -1

Summary of the Values

  • sinθ=22\sin \theta = \frac{\sqrt{2}}{2}
  • cosθ=22\cos \theta = -\frac{\sqrt{2}}{2}
  • tanθ=1\tan \theta = -1
  • cscθ=2\csc \theta = \sqrt{2}
  • secθ=2\sec \theta = -\sqrt{2}
  • cotθ=1\cot \theta = -1

Would you like more details on how any of these values were derived or additional explanations?


Here are five related questions that might help expand your understanding:

  1. How do we determine the signs of trigonometric functions in different quadrants?
  2. What is the significance of a point on the unit circle for determining trigonometric values?
  3. How do we calculate the trigonometric functions for special angles like 4545^\circ or π4\frac{\pi}{4}?
  4. Why does the unit circle have a radius of 1, and how does that simplify calculations?
  5. How would the values change if θ\theta were in a different quadrant?

Tip: Remember that each trigonometric function has a reciprocal function, making it easy to find values like cscθ\csc \theta once you know sinθ\sin \theta.

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Math Problem Analysis

Mathematical Concepts

Trigonometry
Unit Circle
Circular Functions

Formulas

sin θ = y-coordinate
cos θ = x-coordinate
tan θ = sin θ / cos θ
csc θ = 1 / sin θ
sec θ = 1 / cos θ
cot θ = cos θ / sin θ

Theorems

Unit Circle Theorem
Reciprocal Identities

Suitable Grade Level

Grades 10-12