Complete the proof of the identity by choosing the Rule that justifies each step. 1 (1- sinx)(1+ sinx) = %3D 1+tan x To see a detailed description of a Rule, select the More Information Button to the right of the Rule. Statement Rule (1 - sinx) (1 + sinx) = 1 – sin x Rule ? = cos x Rule ? 1 Rule ? %3D sec x 1 Rule ? 1+ tan x

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
Topic Video
Question
## Proof of Trigonometric Identity

### Problem Statement
Complete the proof of the identity by choosing the rule that justifies each step.

\[
(1 - \sin x)(1 + \sin x) = \frac{1}{1 + \tan^{2} x}
\]

To see a detailed description of a rule, select the "More Information" button to the right of the Rule.

### Steps in Proof
**Statement | Rule**

1. \((1 - \sin x)(1 + \sin x)\)

2. \(= 1 - \sin^{2} x\) | Rule ?

3. \(= \cos^{2} x\) | Rule ?

4. \(= \frac{1}{\sec^{2} x}\) | Rule ?

5. \(= \frac{1}{1 + \tan^{2} x}\) | Rule ?

### Explanation of Steps and Rules

1. The left-hand side expression \((1 - \sin x)(1 + \sin x)\) can be simplified using the difference of squares formula, \(a^2 - b^2\)
2. Using the difference of squares formula:
   \[
   a^2 - b^2 = (a - b)(a + b)
   \]
   where \(a = 1\) and \(b = \sin x\), we get:
   \[
   1 - \sin^2 x
   \]
3. According to the Pythagorean identity:
   \[
   \sin^2 x + \cos^2 x = 1
   \]
   rearranging this, we get:
   \[
   \cos^2 x = 1 - \sin^2 x
   \]
   Therefore:
   \[
   1 - \sin^2 x = \cos^2 x
   \]
4. Recognizing that \(\sec x = \frac{1}{\cos x}\), we can write:
   \[
   \cos^2 x = \frac{1}{\sec^2 x}
   \]
5. Using another Pythagorean identity for tangent and secant:
   \[
   1 + \tan^2 x = \sec^2 x
   \]
   we can substitute \(\sec^2 x\) with \(1 + \tan^2 x\)
Transcribed Image Text:## Proof of Trigonometric Identity ### Problem Statement Complete the proof of the identity by choosing the rule that justifies each step. \[ (1 - \sin x)(1 + \sin x) = \frac{1}{1 + \tan^{2} x} \] To see a detailed description of a rule, select the "More Information" button to the right of the Rule. ### Steps in Proof **Statement | Rule** 1. \((1 - \sin x)(1 + \sin x)\) 2. \(= 1 - \sin^{2} x\) | Rule ? 3. \(= \cos^{2} x\) | Rule ? 4. \(= \frac{1}{\sec^{2} x}\) | Rule ? 5. \(= \frac{1}{1 + \tan^{2} x}\) | Rule ? ### Explanation of Steps and Rules 1. The left-hand side expression \((1 - \sin x)(1 + \sin x)\) can be simplified using the difference of squares formula, \(a^2 - b^2\) 2. Using the difference of squares formula: \[ a^2 - b^2 = (a - b)(a + b) \] where \(a = 1\) and \(b = \sin x\), we get: \[ 1 - \sin^2 x \] 3. According to the Pythagorean identity: \[ \sin^2 x + \cos^2 x = 1 \] rearranging this, we get: \[ \cos^2 x = 1 - \sin^2 x \] Therefore: \[ 1 - \sin^2 x = \cos^2 x \] 4. Recognizing that \(\sec x = \frac{1}{\cos x}\), we can write: \[ \cos^2 x = \frac{1}{\sec^2 x} \] 5. Using another Pythagorean identity for tangent and secant: \[ 1 + \tan^2 x = \sec^2 x \] we can substitute \(\sec^2 x\) with \(1 + \tan^2 x\)
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 7 images

Blurred answer
Knowledge Booster
Fundamentals of Trigonometric Identities
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, trigonometry and related others by exploring similar questions and additional content below.
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