The problem ask to find the value of the cos(infinity) and the best answer, base on my further calculation and formulation that came up to a solution that leads me to an answer that the cos(infinity) is undefined but it has a range of (-1,1). I hope you are satisfied with my answer and feel free to ask for more
Answer:
Trinomial.
Step-by-step explanation:
Note how much terms there are in the given expressions:
Term 1: 
Term 2: 
Term 3: 
Note each meaning of the terms:
Monomial: Having only one term.
Binomial: Having two terms.
Trinomial: Having three terms.
Polynomial: Typically used to describe expressions with 4 or more terms.
In this case, there are only 3 terms, and so your answer is Trinomial.
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Answer:

Step-by-step explanation:
we know that

Remember the identity

step 1
Find the value of 
we have that
The angle alpha lie on the III Quadrant
so
The values of sine and cosine are negative

Find the value of sine

substitute




step 2
Find the value of 
we have that
The angle beta lie on the IV Quadrant
so
The value of the cosine is positive and the value of the sine is negative

Find the value of cosine

substitute




step 3
Find cos (α + β)

we have




substitute



Answer:
it would be the last option
Step-by-step explanation: