Answer:
45.40
Step-by-step explanation:
First of all, the shape of rope is not a parabola but a catenary, and all catenaries are similar, defined by:
y=acoshxa
You just have to figure out where the origin is (see picture). The hight of the lowest point on the rope is 20 and the pole is 50 meters high. So the end point must be a+(50−20) above the x-axis. In other words (d/2,a+30) must be a point on the catenary:
a+30=acoshd2a(1)
The lenght of the catenary is given by the following formula (which can be proved easily):
s=asinhx2a−asinhx1a
where x1,x2 are x-cooridanates of ending points. In our case:
80=2asinhd2a
40=asinhd2a(2)
You have to solve the system of two equations, (1) and (2), with two unknowns (a,d). It's fairly straightforward.
Square (1) and (2) and subtract. You will get:
(a+30)2−402=a2
Calculate a from this equation, replace that value into (1) or (2) to evaluate d.
My calculation:
a=353≈11.67
d=703arccosh257≈45.40
Answer: it will take 9 days
Step-by-step explanation:
The water level was initially at 34feet it was receding at the rate of a foot per day. The rate at which it was receding is linear, thus, it is in an arithmetic progression. The formula for the nth term of an arithmetic progression is expressed as
Tn = a+(n-1)d
Where
a is the first term if the sequence
d is the common difference
n is the number of terms.
From the information given,
a = 34 feet because it is the initial height
n is the number of days it will take to get to 26 ft
d = -1 because it is decreasing by 1 foot per day.
Tn = T26 = 26 feet. Therefore, the equation will be
Tn = 34 -1(n-1)
To find for T26,
26= 34 + (n - 1)-1
26 - 34 = -n + 1
n - 1 = 8
n = 8 + 1 = 9
Answer:
Step-by-step explanation:
<u>Sample Space</u>
The sample space of a random experience is a set of all the possible outcomes of that experience. It's usually denoted by the letter 
.
We have a number cube with all faces labeled from 1 to 6. That cube is to be rolled once. The visible number shown in the cube is recorded as the outcome. The possible outcomes are listed as the sample space below:
Now we are required to give the outcomes for the event of rolling a number less than 5. Let's call A to such event. The set of possible outcomes for A has all the numbers from 1 to 4 as follows
Answer:
θ = 
(60° )
Step-by-step explanation:
Using the identity
sin²x + cos²x = 1 ⇒ sin²x = 1 - cos²x
Given
cos²θ - sin²θ = 2 - 5cosθ
cos²θ - (1 - cos²θ) = 2 - 5cosθ
cos²θ - 1 + cos²θ = 2 - 5cosθ
2cos²θ - 1 = 2 - 5cosθ ( subtract 2 - 5cosθ from both sides )
2cos²θ + 5cosθ - 3 = 0 ← in standard form
(cosθ + 3)(2cosθ - 1) = 0 ← in factored form
Equate each factor to zero and solve for θ
cosθ + 3 = 0
cosθ = - 3 ← not possible as - 1 ≤ cosθ ≤ 1
2cosθ - 1 = 0
cosθ = 
, so
θ = 
( ) = ( or 60° )
