Use a Sum-to-Product Formula to show the following. sin(140°) – sin(100°) = -sin(20°) Use a Sum-to-Product Formula for Sine and simplify. sin(140°) – sin(100°) = 2 cos sin 2 sin cos sin(20°) Need Help? Read It Watch It

Trigonometry (11th Edition)
11th Edition
ISBN:9780134217437
Author:Margaret L. Lial, John Hornsby, David I. Schneider, Callie Daniels
Publisher:Margaret L. Lial, John Hornsby, David I. Schneider, Callie Daniels
Chapter1: Trigonometric Functions
Section: Chapter Questions
Problem 1RE: 1. Give the measures of the complement and the supplement of an angle measuring 35°.
icon
Related questions
Question
Could you please write the questions clearly and understandably? Thank you.
**Title: Using Sum-to-Product Formulas**

**Objective:**
Learn how to use the Sum-to-Product Formula to show that:
\[ \sin(140^\circ) - \sin(100^\circ) = -\sin(20^\circ) \]

**Instructions:**

1. **Apply the Sum-to-Product Formula:**

   \[
   \sin(140^\circ) - \sin(100^\circ) = 2 \cos \left( \frac{\_}{2} \right) \sin \left( \frac{\_}{2} \right)
   \]

2. **Calculate specific terms:**

   - \[
     = 2 \cos \left( \frac{240^\circ}{2} \right) \sin \left( \frac{40^\circ}{2} \right)
     \]

   - \[
     = 2 \cos(120^\circ) \sin(20^\circ)
     \]

3. **Continue Simplification:**

   - \[
     = \_\_ \sin(20^\circ)
     \]

4. **Final Answer:**

   - \[
     = -\sin(20^\circ)
     \]

**Support:**
- **Need Help?** Click on "Read It" or "Watch It" for additional guidance.
Transcribed Image Text:**Title: Using Sum-to-Product Formulas** **Objective:** Learn how to use the Sum-to-Product Formula to show that: \[ \sin(140^\circ) - \sin(100^\circ) = -\sin(20^\circ) \] **Instructions:** 1. **Apply the Sum-to-Product Formula:** \[ \sin(140^\circ) - \sin(100^\circ) = 2 \cos \left( \frac{\_}{2} \right) \sin \left( \frac{\_}{2} \right) \] 2. **Calculate specific terms:** - \[ = 2 \cos \left( \frac{240^\circ}{2} \right) \sin \left( \frac{40^\circ}{2} \right) \] - \[ = 2 \cos(120^\circ) \sin(20^\circ) \] 3. **Continue Simplification:** - \[ = \_\_ \sin(20^\circ) \] 4. **Final Answer:** - \[ = -\sin(20^\circ) \] **Support:** - **Need Help?** Click on "Read It" or "Watch It" for additional guidance.
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 2 steps with 1 images

Blurred answer
Recommended textbooks for you
Trigonometry (11th Edition)
Trigonometry (11th Edition)
Trigonometry
ISBN:
9780134217437
Author:
Margaret L. Lial, John Hornsby, David I. Schneider, Callie Daniels
Publisher:
PEARSON
Trigonometry (MindTap Course List)
Trigonometry (MindTap Course List)
Trigonometry
ISBN:
9781305652224
Author:
Charles P. McKeague, Mark D. Turner
Publisher:
Cengage Learning
Algebra and Trigonometry
Algebra and Trigonometry
Trigonometry
ISBN:
9781938168376
Author:
Jay Abramson
Publisher:
OpenStax
Trigonometry (MindTap Course List)
Trigonometry (MindTap Course List)
Trigonometry
ISBN:
9781337278461
Author:
Ron Larson
Publisher:
Cengage Learning