Option B. 13π/6 and Option D. 5π/6
To get the reference angle π/6 for the given angles we will check each angle given in the options.
A. 8π/6
Since 8π/6 means 240° which lies in 3rd quadrant. Therefore reference angle of 240°= 240-180 = 60° or π/3
B. 13π/6
13π/6 means 390° which lies in first quadrant.
Therefore reference angle = 390-360 = 30° or π/6
C. 3π/6
Since 3π/6 means 90° therefore reference angle of 90° is the same as 90°.
Or the reference angle is = π/2
D. 5π/6
5π/6 means angle is 150° which lies in second quadrant therefore reference angle of 150° = 180-150 = 30° or π/6
answer is Option B and D.
Answer:
(a)
Step-by-step explanation:
(a)The degree of a polynomial is the highest power of the unknown variable in the polynomial.
A polynomial is said to be in standard form when it is arranged in descending order/powers of x.
An example of a fourth degree polynomial is: 
We know the polynomial above is in standard form because it is arranged in such a way that the powers of x keeps decreasing.
(b)Polynomials are closed with respect to addition and subtraction. This is as a result of the fact that the powers do not change. Only the coefficients
change. This is illustrated by the two examples below:

The degrees do not change in the above operations. Only the number beside each variable changes. Therefore, the addition and subtraction of polynomials is closed.
Answer:
Expression D
Step-by-step explanation:
all other answers are above 15! hope this helps :D
A discrete variable is a variable which may take only certain discrete values; for example the number of people in a household is a discrete variable which may have the value 1, 2, 3, etc. but cannot have intermediate values such as 1.473 or 3.732.
Choice d) can be represented by a discrete probability distribution, the other choices cannot be so represented.