Article Diary - General Knowledge Digest

Pythagorean Identities

  1. sin²θ+ cos²θ = 1
  2. 1 + tan²θ = sec²θ
  3. 1 + cot²θ = csc ²θ

From (a) sin²θ = 1 − cos²θ i.e. cos²θ = 1 − sin²θ

These are called Pythagorean identities, because, as we will see in their proof, they are the trigonometric version of the Pythagorean theorem. The two identities are simply different versions of (a).

The first shows how we can express sin θ in terms of cos θ; the second shows how we can express cos θ in terms of sin θ.

Note: sin²θ "sine squared theta" means (sin θ)².

Attached Files
There are no attachments for this article.
Comments
There are no comments for this article. Be the first to post a comment.
Name
Email
Security Code Security Code
Related Articles RSS Feed
Trade Names - Quiz Questions and Answers
Viewed 1472 times since Thu, Dec 31, 2009
Variety of Animals
Viewed 1908 times since Sat, Dec 26, 2009
Units of Measurement
Viewed 1785 times since Sat, Dec 19, 2009
British Rule In India
Viewed 1770 times since Thu, Dec 10, 2009
World Famous Battles and Wars
Viewed 2073 times since Wed, Dec 9, 2009
First People - Who were the first to do something?
Viewed 2994 times since Thu, Jan 14, 2010
Motorola Xoom Tablet with Android 3.0 Honeycomb OS
Viewed 798 times since Wed, Jan 12, 2011
First Expeditioners In World History
Viewed 1637 times since Wed, Jan 13, 2010
Branches of Science and their Definitions
Viewed 4502 times since Sat, Dec 26, 2009
AIEEE 2010 Answer Key - Download AIEEE 2010 Solved Paper
Viewed 1808 times since Mon, Apr 26, 2010
MENU