Answer:
a) the common difference is 20
b) 
c) the common difference is -13
d) 
Step-by-step explanation:
a) what is the common difference of the sequence xn
Looking at the table, we get x_3=16, x_4=36 and x_5= 56
Deterring the common difference by subtracting x_4 from x_3 we get
36-16 =20
So, the common difference is 20
b) what is x_8? what is x_12
The formula used is: 
We know common difference d= 20, we need to find 
Using
we can find 

So, We have 
Now finding 

So, 
Now finding 

So, 
c) what is the common difference of the sequence 
Looking at the table, we get a_7=104, a_8=91 and a_9= 78
Deterring the common difference by subtracting a_7 from a_8 we get
91-104 =-13
So, the common difference is -13
d) what is a_12? what is a_15?
The formula used is: 
We know common difference d= -13, we need to find 
Using
we can find 

So, We have 
Now finding
, put n=12

So, 
Now finding
, put n=15

So, 
Answer:
is an even function.
Step-by-step explanation:
Recall when it means when a function is even or odd. An even function has the following property:

And an odd function has the following property:

So, let's test some values for cos(x).
Let's use π/3:

From the unit circle, was can see that this is 1/2 (refer to the x-coordinate).
Now, let's find -π/3. This is the same as 5π/3. Thus:

And again from the unit circle, we can see that this is 1/2.
Therefore, despite the negative, the function outputs the same value.
Cosine is an even function.
Notes:
Cosine is an even function and sine is an odd function. It's helpful to remember these as they can help you solve some trig problems!
Answer:
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Step-by-step explanation:
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Question:
What is the area of the sector? Either enter an exact answer in terms of π or use 3.14 and enter your answer as a decimal rounded to the nearest hundredth.
Answer:
See Explanation
Step-by-step explanation:
The question is incomplete as the values of radius and central angle are not given.
However, I'll answer the question using the attached figure.
From the attached figure, the radius is 3 unit and the central angle is 120 degrees
The area of a sector is calculated as thus;

Where
represents the central angle and r represents the radius
By substituting
and r = 3
becomes



square units
Solving further to leave answer as a decimal; we have to substitute 3.14 for 
So,
becomes

square units
Hence, the area of the sector in the attached figure is
or 9.42 square units