Answer:
(x-4)² + y² = 100
Step-by-step explanation:
The only circles that have a center at (4 , 0) are :
(x-4)² + y² = 100
(x-4)² + y² = 10
……………………
• (-2 - 4)² + 8² = (-6)² + 64 = 36 + 64 = 100 ≠ 10
Then
The circle (x-4)² + y² = 10 doesn’t contain the point (-2, 8)
• (-2 - 4)² + 8² = 100
Then
The circle (x-4)² + y² = 100 contains the point (-2, 8)
Answer:
2nd choice
Step-by-step explanation:
From the figure, we immediately have
cos(θ) = 8/17
sin(θ) = 15/17
By definition of tangent,
tan(2θ) = sin(2θ)/cos(2θ)
Recall the double angle identities:
sin(2θ) = 2 sin(θ) cos(θ)
cos(2θ) = cos²(θ) - sin²(θ) = 2 cos²(θ) - 1
Then
tan(2θ) = (2 sin(θ) cos(θ)) / (2 cos²(θ) - 1)
tan(2θ) = (2 × 15/17 × 8/17) / (2 × (8/17)² - 1)
tan(2θ) = -240/161
150 divided by 25 is 6, so I think it would be 6 hours to equal the total cost.