Sin x = - 1/2
where (-360 < x < 360)

-30, 210 and 330 degrees

Step-by-step explanation:

Given the expression Sin x = - 1/2

x = arcsin(-1/2)

x = -30 degrees

Since sin is negative in the third and fourth quadrant

x = 180 + 30

x = 210 degrees

In the fourth quadrant

x = 360 - 30

x = 330

Hence the value of x within the interval -360 < x < 360 are -30, 210 and 330 degrees

Answer and Explanation:

Given : The random variable x has the following probability distribution.

To find :

a. Is this probability distribution valid? Explain and list the requirements for a valid probability distribution.

b. Calculate the expected value of x.

c. Calculate the variance of x.

d. Calculate the standard deviation of x.

Solution :

First we create the table as per requirements,

x      P(x)         xP(x)           x²            x²P(x)

0    0.25           0               0                0

1     0.20        0.20             1              0.20

2    0.15          0.3               4             0.6

3    0.30         0.9               9             2.7

4    0.10          0.4               16             1.6

   ∑P(x)=1     ∑xP(x)=1.8               ∑x²P(x)=5.1

a) To determine that table shows a probability distribution we add up all five probabilities if the sum is 1 then it is a valid distribution.

Yes it is a probability distribution.

b) The expected value of x is defined as

c) The variance of x is defined as

d) The standard deviation of x is  defined as