Expand the target expression:
A sin(x + ϕ) = A (sin(x) cos(ϕ) + cos(x) sin(ϕ)) = -2 sin(x) + 4 cos(x)
Then we have
A cos(ϕ) = -2
A sin(ϕ) = 4
Recall that sin²(x) + cos²(x) = 1 for all x. Then
(A cos(ϕ))² + (A sin(ϕ))² = (-2)² + 4²
A² (cos²(ϕ) + sin²(ϕ)) = 4 + 16
A² = 20
A = √20 = 2√5
Also recall that tan(x) = sin(x)/cos(x) by definition. Then
(A sin(ϕ)) / (A cos(ϕ)) = 4 / (-2)
tan(ϕ) = -2
ϕ = arctan(-2) = -arctan(2)
It would be C.
1 + .4 = 1.4
Answer:
B. (2, 2), (6, 4), (8, 10), (9, 28)
Step-by-step explanation:
I hope this helped! :D
Step 1 he had to multiply the $22.75 times 3 weeks it should have been
($22.75 x 3) + $32.75 - $14.25
$68.25 + 32.75 - $14.25
$86.75
Answer: Bridget was thinking of the number 2.95
Step-by-step explanation:
21.9 / 2 = 10.95
10.95 - 8 = 2.95