Cos2x-1

Cos2x-1

Input
cos(2 x) – 1
Roots
x = pi n, n element Z
Series expansion at x=0
-2 x^2 + (2 x^4)/3 – (4 x^6)/45 + (2 x^8)/315 + O(x^9)
(Taylor series)
Derivative
d/dx(cos(2 x) – 1) = -2 sin(2 x)
Indefinite integral
integral (-1 + cos(2 x)) dx = sin(x) cos(x) – x + constant
Global maxima
max{cos(2 x) – 1} = 0 at x = pi n for integer n
Definite integral over a half-period
integral_0^(pi/2) (-1 + cos(2 x)) dx = -pi/2~~-1.5708
Definite integral over a period
integral_0^pi (-1 + cos(2 x)) dx = -pi~~-3.14159
Definite integral mean square
integral_0^pi (-1 + cos(2 x))^2/pi dx = 3/2 = 1.5
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