Discover the answers you need at Westonci.ca, where experts provide clear and concise information on various topics. Discover in-depth answers to your questions from a wide network of experts on our user-friendly Q&A platform. Explore comprehensive solutions to your questions from knowledgeable professionals across various fields on our platform.

Find the value of [tex]\left(\sec ^2 \theta - 1\right)\left(1 - \csc^2 \theta\right)[/tex].

Sagot :

To solve the expression [tex]\(\left(\sec^2 \theta - 1\right)\left(1 - \csc^2 \theta\right)\)[/tex], let's break it down into detailed steps:

1. Expression for [tex]\(\sec^2 \theta - 1\)[/tex]:
[tex]\[ \sec^2 \theta = \frac{1}{\cos^2 \theta} \][/tex]
Therefore,
[tex]\[ \sec^2 \theta - 1 = \frac{1}{\cos^2 \theta} - 1 = \frac{1 - \cos^2 \theta}{\cos^2 \theta} \][/tex]
Using the Pythagorean identity [tex]\( \sin^2 \theta + \cos^2 \theta = 1 \)[/tex], we get:
[tex]\[ 1 - \cos^2 \theta = \sin^2 \theta \][/tex]
Thus,
[tex]\[ \sec^2 \theta - 1 = \frac{\sin^2 \theta}{\cos^2 \theta} = \tan^2 \theta \][/tex]

2. Expression for [tex]\(1 - \csc^2 \theta\)[/tex]:
[tex]\[ \csc^2 \theta = \frac{1}{\sin^2 \theta} \][/tex]
Therefore,
[tex]\[ 1 - \csc^2 \theta = 1 - \frac{1}{\sin^2 \theta} = \frac{\sin^2 \theta - 1}{\sin^2 \theta} \][/tex]
Using the Pythagorean identity [tex]\( \sin^2 \theta + \cos^2 \theta = 1 \)[/tex], we get:
[tex]\[ \sin^2 \theta - 1 = -\cos^2 \theta \][/tex]
Thus,
[tex]\[ 1 - \csc^2 \theta = \frac{-\cos^2 \theta}{\sin^2 \theta} = -\cot^2 \theta \][/tex]

3. Combining the results:
We found that:
[tex]\[ \sec^2 \theta - 1 = \tan^2 \theta \][/tex]
[tex]\[ 1 - \csc^2 \theta = -\cot^2 \theta \][/tex]
Therefore,
[tex]\[ \left(\sec^2 \theta - 1\right)\left(1 - \csc^2 \theta\right) = \left(\tan^2 \theta\right) \left(-\cot^2 \theta\right) \][/tex]

4. Simplifying the product:
Recall that [tex]\(\tan \theta = \frac{\sin \theta}{\cos \theta}\)[/tex] and [tex]\(\cot \theta = \frac{\cos \theta}{\sin \theta}\)[/tex]. Hence,
[tex]\[ \tan^2 \theta \cdot \cot^2 \theta = \left(\frac{\sin^2 \theta}{\cos^2 \theta} \cdot \frac{\cos^2 \theta}{\sin^2 \theta}\right) = 1 \][/tex]
Therefore,
[tex]\[ \left(\sec^2 \theta - 1\right)\left(1 - \csc^2 \theta\right) = \left(\tan^2 \theta\right) \left(-\cot^2 \theta\right) = \left(\tan^2 \theta\right) \left(-1 \cdot \frac{1}{\tan^2 \theta}\right) = -1 \][/tex]

Thus, the value of [tex]\(\left(\sec^2 \theta - 1\right)\left(1 - \csc^2 \theta\right)\)[/tex] is [tex]\(-1\)[/tex].
Thanks for stopping by. We are committed to providing the best answers for all your questions. See you again soon. Thanks for stopping by. We strive to provide the best answers for all your questions. See you again soon. We're glad you visited Westonci.ca. Return anytime for updated answers from our knowledgeable team.