Q:

# What Is the Pythagorean Identity?

A:

The Pythagorean identity is sin2Ø + cos2Ø = 1. This is called the fundamental identity in trigonometry. Two other identities are 1+ tan2Ø = sec2Ø and 1+ cot2Ø = cosec2Ø.

## Keep Learning

These identities are called Pythagorean identities as they are based on the Pythagorean theorem developed by the Greek mathematician Pythagoras. This theorem has to do with right triangles, and it is applied in trigonometry. Trigonometry was originally developed for making calculations based on the use of the Pythagorean theorem.

These identities were arrived at using the unit circle. A unit circle is a circle having one unit as its radius. A right triangle is formed within this unit circle to arrive at the Pythagorean identities.

## Related Questions

• A: The positive square root of 99 is 9.95, and the negative square root is -9.95. The square root of 99 can also be re-written as 3 times the square root of 1... Full Answer >
Filed Under:
• A: A pint is not bigger than a quart. A pint is half the size of a quart, and it contains 16 ounces or 2 cups. Full Answer >
Filed Under:
• A: To make a multiplication chart for kids, fill in the first row and the first column of a table with the same numbers. It's common to include the numbers on... Full Answer >
Filed Under:
• A: The factors of 10 are 1, 2, 5 and 10. These factors also include the negative numbers -1, -2, -5 and -10. A factor of a number is a whole number that can b... Full Answer >
Filed Under:
PEOPLE SEARCH FOR