Answer: -1
Step-by-step explanation:
slope formula: y=mx+b
m=slope
y=(-1)x+8
Using the cosine double angle formula,

(Note I took the positive case since
terminates in the first quadrant)
Using the Pythagorean identity,

(Note I took the positive case since
terminates in the first quadrant)
We will turn the left side into the right side.

Use the identity:



Now use the identity
solved for sin^2 x and for cos^2 x.




i think its D, (change my mind)
Answer:
we get 
Step-by-step explanation:
We are given: 
We need to find 
Note: Since question is not clear, I am assuming that we need to find 
Solving:

We know that 
Using formula and simplifying

So, we get 