Answer:
#3
Step-by-step explanation:
there is a 2 to one ratio of string to precussion
Givens
y = 2
x = 1
z(the hypotenuse) = √(2^2 + 1^2) = √5
Cos(u) = x value / hypotenuse = 1/√5
Sin(u) = y value / hypotenuse = 2/√5
Solve for sin2u
Sin(2u) = 2*sin(u)*cos(u)
Sin(2u) = 2(
) = 4/5
Solve for cos(2u)
cos(2u) = - sqrt(1 - sin^2(2u))
Cos(2u) = - sqrt(1 - (4/5)^2 )
Cos(2u) = -sqrt(1 - 16/25)
cos(2u) = -sqrt(9/25)
cos(2u) = -3/5
Solve for Tan(2u)
tan(2u) = sin(2u) / cos(2u) = 4/5// - 3/5 = - 0.8/0.6 = - 1.3333 = - 4/3
Notes
One: Notice that you would normally rationalize the denominator, but you don't have to in this case. The formulas are such that they perform the rationalizations themselves.
Two: Notice the sign on the cos(2u). The sin is plus even though the angle (2u) is in the second quadrant. The cos is different. It is about 126 degrees which would make it a negative root (9/25)
Three: If you are uncomfortable with the tan, you could do fractions.

Answer:
2/3
Step-by-step explanation:
Simplify the following:
(8/27)^(1/3)
Hint: | For all n>=0, (m/n)^(1/3) = (m^(1/3))/(n^(1/3)).
(8/27)^(1/3) = (8^(1/3))/(27^(1/3)):
(8^(1/3))/(27^(1/3))
Hint: | Simplify radicals.
27^(1/3) = (3^3)^(1/3) = 3:
(8^(1/3))/3
Hint: | Simplify radicals.
8^(1/3) = (2^3)^(1/3) = 2:
Answer: 2/3
Step-by-step explanation:
First step is to identify what the problem is asking for and what is given.
9 laps in 28 minutes
Searching for number of laps in 1 hour and 15 min.
1 hour + 15 min. = 75 minutes convert to minutes
9 laps / 28 minutes = x laps / 75 minutes create an equation
9/28 = x/75
9*75 = 28x cross multiply
675 = 28x
x = 675/28 = 24.12 simplify
Melanie can run 24 complete laps in 1 hour and 15 minutes.