Table of contents
- 0. Review of College Algebra4h 43m
- 1. Measuring Angles39m
- 2. Trigonometric Functions on Right Triangles2h 5m
- 3. Unit Circle1h 19m
- 4. Graphing Trigonometric Functions1h 19m
- 5. Inverse Trigonometric Functions and Basic Trigonometric Equations1h 41m
- 6. Trigonometric Identities and More Equations2h 34m
- 7. Non-Right Triangles1h 38m
- 8. Vectors2h 25m
- 9. Polar Equations2h 5m
- 10. Parametric Equations1h 6m
- 11. Graphing Complex Numbers1h 7m
2. Trigonometric Functions on Right Triangles
Trigonometric Functions on Right Triangles
Problem 34c
Textbook Question
Concept Check Suppose that the point (x, y) is in the indicated quadrant. Determine whether the given ratio is positive or negative. Recall that r = √(x² + y²) .(Hint: Drawing a sketch may help.) IV , x/y
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1
<insert step 1> Draw a coordinate plane and label the quadrants. Quadrant IV is located in the lower right section of the plane.>
<insert step 2> Recall the signs of x and y in Quadrant IV: x is positive and y is negative.>
<insert step 3> Consider the ratio x/y. Since x is positive and y is negative, the ratio x/y will be negative.>
<insert step 4> Visualize or sketch the point (x, y) in Quadrant IV to reinforce the understanding of the signs of x and y.>
<insert step 5> Conclude that in Quadrant IV, the ratio x/y is negative.>
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Quadrants of the Cartesian Plane
The Cartesian plane is divided into four quadrants based on the signs of the x and y coordinates. In Quadrant IV, x is positive and y is negative. Understanding the signs of coordinates in each quadrant is essential for determining the positivity or negativity of trigonometric ratios.
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Trigonometric Ratios
Trigonometric ratios, such as sine, cosine, and tangent, are defined based on the relationships between the sides of a right triangle. For the ratio x/y, this represents the tangent function. Knowing how these ratios behave in different quadrants helps in assessing their signs.
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Distance Formula and Radius (r)
The radius r is calculated using the formula r = √(x² + y²), which represents the distance from the origin to the point (x, y). In Quadrant IV, since x is positive and y is negative, r will always be positive. This concept is crucial for understanding the geometric interpretation of trigonometric functions.
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