radius* 2=diameter so no diameter and radius aren't the same thing because radius is half the distance across the circle and diameter is the full distance across the circle.
Recall the sum identity for cosine:
cos(a + b) = cos(a) cos(b) - sin(a) sin(b)
so that
cos(a + b) = 12/13 cos(a) - 8/17 sin(b)
Since both a and b terminate in the first quadrant, we know that both cos(a) and sin(b) are positive. Then using the Pythagorean identity,
cos²(a) + sin²(a) = 1 ⇒ cos(a) = √(1 - sin²(a)) = 15/17
cos²(b) + sin²(b) = 1 ⇒ sin(b) = √(1 - cos²(b)) = 5/13
Then
cos(a + b) = 12/13 • 15/17 - 8/17 • 5/13 = 140/221
Answer:
Vertical
Step-by-step explanation:
Vertical line crossing the x-axis at 6. It does not cross the y-axis.
Answer:
C. 2/3
Step-by-step explanation:
12 hours (5880 divided by 490)
