Hello,
sin² x-cos² x=sin² x-(1-sin² x)=2sin² x-1
==============================
Answer:

But we need to calculate the mean with the following formula:

And replacing we got:

And for the sample variance we have:

And thi is the best estimator for the population variance since is an unbiased estimator od the population variance 

Step-by-step explanation:
For this case we have the following data:
1.04,1.00,1.13,1.08,1.11
And in order to estimate the population variance we can use the sample variance formula:

But we need to calculate the mean with the following formula:

And replacing we got:

And for the sample variance we have:

And thi is the best estimator for the population variance since is an unbiased estimator od the population variance 

Step-by-step explanation:
The answer is 130° since you subtract 4° from both sides
Answer:
Question 2 is y = 1/2 x - 2
Question 3 is y=-2x+4
Question 4 is y = x + 3
Your other questions don't have pictures of the graph so I can't solve them sorry. Have a good day.
Answer:
Width=28 1/3 Length=51 2/3
Step-by-step explanation:
1. Create an equation
x+(2x-5)=80
2. Solve
x+(2x-5)=80
3x-5=80
3x-5+5=80+5
3x/3=85/3
x=28 1/3
So, if x=28 1/3
85/3x2=170/3
56 2/3-5
So, Length=51 2/3