A minimum occurs where the first derivative is 0 (the tangent line is horizontal), and the second derivative is positive (concave up). The simplest example of this is a positive parabola, like y = x², which has a relative minimum at its vertex.
The probability of rolling an even number on the first dice is 1/2(3/6) The probability of rolling an even number on the first dice is also 1/2 (3/6) So the probability of getting two even numbers on both dice is 1/2*1/2=1/4
