could someone please refresh my memory of the basic trig functions?

ex) cos^2 + sin^2 = 1?

That is a trig identity.

http://www.sosmath.com/trig/Trig5/trig5/trig5.html

The basic trigonometric functions are sine, cosine, and tangent. These functions relate the angles of a right triangle to the lengths of its sides.

1. Sine (sin): In a right triangle, the sine of an angle is defined as the ratio of the length of the side opposite to the angle to the length of the hypotenuse. It is denoted as sin(θ).

2. Cosine (cos): The cosine of an angle is defined as the ratio of the length of the adjacent side to the angle to the length of the hypotenuse. It is denoted as cos(θ).

3. Tangent (tan): The tangent of an angle is defined as the ratio of the length of the side opposite to the angle to the length of the adjacent side. It is denoted as tan(θ).

Now, let's discuss the trig identity you mentioned:

cos^2(θ) + sin^2(θ) = 1

This is known as the Pythagorean identity for trigonometric functions. It holds true for any angle θ. The identity states that the square of the cosine of an angle added to the square of the sine of the same angle always equals 1.

To refresh your memory or learn more about trigonometric functions and identities, you can visit the website you provided: http://www.sosmath.com/trig/Trig5/trig5/trig5.html. This resource will provide a comprehensive and detailed explanation of trigonometric concepts, expressions, and identities.