Cosine of 0 degrees equals 1. Cosine represents ratio of adjacent side to hypotenuse in right triangles. Can be expressed as 1/1 in fractions or 1.0 in decimals
Cos 0 equals 1 in trigonometry. Cosine function relates to angles of a right triangle. Cosine formula: Cos X = Adjacent Side / Hypotenuse Side
Trigonometric ratios relate sides of a triangle taken two at a time. One angle must be right for trigonometric ratios to work. Base is horizontal, adjacent side is vertical, hypotenuse is connecting segment
The derivative of cos^2x is -sin^2x. The derivative gives the slope of tangent at points of contact
The value of cos 2pi/3 is -0.5. In degrees, it equals cos(120°). The angle 2pi/3 lies between pi/2 and pi in the Second Quadrant
Cos2x is a double angle identity for finding cosine values for 2x. Four main forms exist: cos2x = cos2x - sin2x, cos2x = 2cos2x - 1, cos2x = 1 - 2sin2x, cos2x = (1 - tan2x)/(1 + tan2x)