how to find the period of an equation
imagine the equation y = -5cos(1/2)x in variables. so y = acos(b)x where a = -5 and b = 1/2. to find the period of a cos equation the formula is 2pi / b. with the equation y = -5cos(1/2)x b equals 1/2. plug b into the formula of 2pi / b. 2pi / 1/2 or 2pi / 0.5 which gives you the answer of 4pi.