Find the exact value for the expression under the given conditions. 5 5 cos (a +ß), sin a = - for a in Quadrant III and cos ß=- 13 12 cos (a + B)= X for ß in Quadrant II.

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°.
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**Problem Statement:**

Find the exact value for the expression under the given conditions.

Given:
\[
\cos (\alpha + \beta), \quad \sin \alpha = -\frac{5}{13} \quad \text{for } \alpha \text{ in Quadrant III} \quad \text{and}\quad \cos \beta = -\frac{5}{12} \quad \text{for } \beta \text{ in Quadrant II}.
\]

**Calculation Area:**
\[
\cos (\alpha + \beta) = \text{ (input box)}
\]

There is an interactive area provided to input and verify your answer. The interface allows you to enter mathematical symbols and expressions.

**Solution Steps Overview:**

To solve for \(\cos(\alpha + \beta)\), we can use the angle addition formula for cosine:

\[
\cos (\alpha + \beta) = \cos \alpha \cos \beta - \sin \alpha \sin \beta
\]

Given values are:

\[
\sin \alpha = -\frac{5}{13} \quad \text{(for } \alpha \text{ in Quadrant III)}
\]
\[
\cos \beta = -\frac{5}{12} \quad \text{(for } \beta \text{ in Quadrant II)}
\]

1. First find \(\cos \alpha\):
In Quadrant III, both sine and cosine are negative. Using the Pythagorean identity:
\[
\sin^2 \alpha + \cos^2 \alpha = 1 
\]
\[
\left(-\frac{5}{13}\right)^2 + \cos^2 \alpha = 1 
\]
\[
\frac{25}{169} + \cos^2 \alpha = 1 
\]
\[
\cos^2 \alpha = 1 - \frac{25}{169} 
\]
\[
\cos^2 \alpha = \frac{144}{169} 
\]
Since \(\alpha\) is in Quadrant III, \(\cos \alpha\) is negative:
\[
\cos \alpha = -\frac{12}{13} 
\]

2. Find \(\sin \beta\):
In Quadrant II, sine is positive and cosine is negative. Using the Pythagorean identity:
\[
Transcribed Image Text:**Problem Statement:** Find the exact value for the expression under the given conditions. Given: \[ \cos (\alpha + \beta), \quad \sin \alpha = -\frac{5}{13} \quad \text{for } \alpha \text{ in Quadrant III} \quad \text{and}\quad \cos \beta = -\frac{5}{12} \quad \text{for } \beta \text{ in Quadrant II}. \] **Calculation Area:** \[ \cos (\alpha + \beta) = \text{ (input box)} \] There is an interactive area provided to input and verify your answer. The interface allows you to enter mathematical symbols and expressions. **Solution Steps Overview:** To solve for \(\cos(\alpha + \beta)\), we can use the angle addition formula for cosine: \[ \cos (\alpha + \beta) = \cos \alpha \cos \beta - \sin \alpha \sin \beta \] Given values are: \[ \sin \alpha = -\frac{5}{13} \quad \text{(for } \alpha \text{ in Quadrant III)} \] \[ \cos \beta = -\frac{5}{12} \quad \text{(for } \beta \text{ in Quadrant II)} \] 1. First find \(\cos \alpha\): In Quadrant III, both sine and cosine are negative. Using the Pythagorean identity: \[ \sin^2 \alpha + \cos^2 \alpha = 1 \] \[ \left(-\frac{5}{13}\right)^2 + \cos^2 \alpha = 1 \] \[ \frac{25}{169} + \cos^2 \alpha = 1 \] \[ \cos^2 \alpha = 1 - \frac{25}{169} \] \[ \cos^2 \alpha = \frac{144}{169} \] Since \(\alpha\) is in Quadrant III, \(\cos \alpha\) is negative: \[ \cos \alpha = -\frac{12}{13} \] 2. Find \(\sin \beta\): In Quadrant II, sine is positive and cosine is negative. Using the Pythagorean identity: \[
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