If you consult the unit circle, you will see that:

3pi/4 in degrees is 3pi/4 * 180/pi = 3/4 * 180 = 135 degrees. And please refer to the attachment to how you can obtain the values above.
Now, lets multiply it together.

So, <span>cos(3pi/4)sin(3pi/4) =
-1/2</span>
Answer:
Mean = 8
Variance = 7.36
Standard Deviation = 2.7129
Step-by-step explanation:
This is a binomial distribution with parameters, n and p.
Where
n is sample size (given as 100)
p is the probability of success, or probability of defective (given as 8% or 0.08)
The mean, variance, standard deviation formula for binomial distribution is shown below:
Mean = 
Variance = 
Standard Deviation = 
Where q would be probability of failure, or "1 - p"
Thus,
n = 100
p = 0.08
q = 1 - 0.08 = 0.92
SO, we have:
Mean = 
Variance = 
Standard Deviation = 
When the 10 is to a negative power you move the decimal to the left. in this case its 5 spots. i believe your answer is .00005003
If each of the 28 students made at least $25, you would multiply 28 and 25 together to obtain the least amount of money the class raised. That gets, 28x25 = 700. The class made at least $700.