Answer:
The work is in the explanation.
Step-by-step explanation:
The sine addition identity is:
.
The sine difference identity is:
.
The cosine addition identity is:
.
The cosine difference identity is:
.
We need to find a way to put some or all of these together to get:
.
So I do notice on the right hand side the 
and the 
.
Let's start there then.
There is a plus sign in between them so let's add those together:
![=[\sin(a+b)]+[\sin(a-b)]](https://tex.z-dn.net/?f=%3D%5B%5Csin%28a%2Bb%29%5D%2B%5B%5Csin%28a-b%29%5D)
![=[\sin(a)\cos(b)+\cos(a)\sin(b)]+[\sin(a)\cos(b)-\cos(a)\sin(b)]](https://tex.z-dn.net/?f=%3D%5B%5Csin%28a%29%5Ccos%28b%29%2B%5Ccos%28a%29%5Csin%28b%29%5D%2B%5B%5Csin%28a%29%5Ccos%28b%29-%5Ccos%28a%29%5Csin%28b%29%5D)
There are two pairs of like terms. I will gather them together so you can see it more clearly:
![=[\sin(a)\cos(b)+\sin(a)\cos(b)]+[\cos(a)\sin(b)-\cos(a)\sin(b)]](https://tex.z-dn.net/?f=%3D%5B%5Csin%28a%29%5Ccos%28b%29%2B%5Csin%28a%29%5Ccos%28b%29%5D%2B%5B%5Ccos%28a%29%5Csin%28b%29-%5Ccos%28a%29%5Csin%28b%29%5D)
So this implies:
Divide both sides by 2:
By the symmetric property we can write:
Step-by-step explanation:
i think this is the answer if it's wrong I'm sorry
A: the formula would be f(x) = P(R) ^T or f(x) = Principle(rate)^time
B: f(x) = 20,000(0.85)^5
C: = 8,874.10625
D: Yes, the final answer makes sense compared to the origional cost of the car in relation to the formula. As well, time decreases the value of a car, so for the cost to be so low only makes sense due to the cars decrease in value or an extended and elongated amount of time.
E: You can solve this equation graphically by plotting th point at 20,000 and then taking 85% of 20,000 and plotting it each time until you get to the fifth year.
F(x)=5x
normal domain: all real numbers
practical domain: <span>all positive integers
</span>becasue we can substituent with any positive integer in the place of x
