Table of contents
- 0. Fundamental Concepts of Algebra3h 29m
- 1. Equations and Inequalities3h 27m
- 2. Graphs1h 43m
- 3. Functions & Graphs2h 17m
- 4. Polynomial Functions1h 54m
- 5. Rational Functions1h 23m
- 6. Exponential and Logarithmic Functions2h 28m
- 7. Measuring Angles40m
- 8. Trigonometric Functions on Right Triangles2h 5m
- 9. Unit Circle1h 19m
- 10. Graphing Trigonometric Functions1h 19m
- 11. Inverse Trigonometric Functions and Basic Trig Equations1h 41m
- 12. Trigonometric Identities 2h 34m
- 13. Non-Right Triangles1h 38m
- 14. Vectors2h 25m
- 15. Polar Equations2h 5m
- 16. Parametric Equations1h 6m
- 17. Graphing Complex Numbers1h 7m
- 18. Systems of Equations and Matrices3h 6m
- 19. Conic Sections2h 36m
- 20. Sequences, Series & Induction1h 15m
- 21. Combinatorics and Probability1h 45m
- 22. Limits & Continuity1h 49m
- 23. Intro to Derivatives & Area Under the Curve2h 9m
8. Trigonometric Functions on Right Triangles
Trigonometric Functions on Right Triangles
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Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
If tanθ=512, find the values of the five other trigonometric functions. Rationalize the denominators if necessary.
A
sinθ=1312,cosθ=135,cotθ=125,secθ=513,cscθ=1213
B
sinθ=135,cosθ=1312,cotθ=125,secθ=1213,cscθ=513
C
sinθ=1312,cosθ=135,cotθ=−125,secθ=−513,cscθ=−1213
D
sinθ=135,cosθ=1312,cotθ=−125,secθ=−1213,cscθ=−513

1
Start by recalling the definition of the tangent function: \( \tan\theta = \frac{\text{opposite}}{\text{adjacent}} \). Given \( \tan\theta = \frac{12}{5} \), we can consider a right triangle where the opposite side is 12 and the adjacent side is 5.
Use the Pythagorean theorem to find the hypotenuse of the triangle. The theorem states \( a^2 + b^2 = c^2 \), where \( a \) and \( b \) are the legs of the triangle, and \( c \) is the hypotenuse. Substitute the known values: \( 12^2 + 5^2 = c^2 \).
Solve for \( c \) to find the hypotenuse. This will give you the length of the hypotenuse, which is necessary to find the sine and cosine of \( \theta \).
Calculate \( \sin\theta \) and \( \cos\theta \) using the definitions: \( \sin\theta = \frac{\text{opposite}}{\text{hypotenuse}} \) and \( \cos\theta = \frac{\text{adjacent}}{\text{hypotenuse}} \). Substitute the values from the triangle.
Determine the remaining trigonometric functions: \( \cot\theta = \frac{1}{\tan\theta} \), \( \sec\theta = \frac{1}{\cos\theta} \), and \( \csc\theta = \frac{1}{\sin\theta} \). Rationalize the denominators if necessary.
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