Four numbers from the set 0 to 9, including 0 and 9, are used to create a personal identification number. Once a number is used,
it cannot be reused. How many possible outcomes exist for the situation? How many possible outcomes begin with a 0? What is the theoretical probability of choosing a personal identification number that begins with a 0?
trigonometric function whose value for the complement of an angle is equal to the value of a given trigonometric function of the angle itself the sine is the cofunction of the cosine.
