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
Largest, Smallest, Highest and Longest in India
Viewed 3029 times since Fri, Jan 15, 2010
Branches of Science and their Definitions
Viewed 8116 times since Sat, Dec 26, 2009
British Rule In India
Viewed 3281 times since Thu, Dec 10, 2009
Variety of Animals
Viewed 3767 times since Sat, Dec 26, 2009
Medical Inventions and Discoveries
Viewed 4143 times since Fri, Jan 15, 2010
Measurement of Sports Fields
Viewed 3639 times since Sat, Jan 2, 2010
Units of Measurement
Viewed 3210 times since Sat, Dec 19, 2009
General Knowledge Quiz To Test Your General Knowledge
Viewed 2589 times since Sat, Nov 7, 2009
Space Terms - Definitions & Glossary of Space Terms
Viewed 3241 times since Sat, Jan 16, 2010
Pioneers in Science - Physics and Chemistry
Viewed 3681 times since Sat, Jan 16, 2010
MENU