For 10 points, name this Greek letter which represents the change of the value of a variable.
A function named for this letter is obtained by taking the limit of the normal distribution as the variance approaches zero. A function named for this letter is equal to zero if two variables are equivalent and one if the variables are different. This letter names another function which contains an infinitely tall spike at x equals zero, but is equal to zero everywhere else. Both Kronecker and Dirac name functions called by this letter. Limits are defined by intervals named for epsilon and this letter. The lowercase version of this Greek letter is added before a variable to represent an infinitesimal amount. For 10 points, name this Greek letter which represents the change of the value of a variable.
A function named for this letter is obtained by taking the limit of the normal distribution as the variance approaches zero.
delta [or delta function; or Kronecker delta (function); or Dirac delta (function)]