Answer:
16.65 ft
Step-by-step explanation:
You want the length of the shortest ladder that will reach a building over an 8 ft high fence that is 4 ft from the building.
As in the attached diagram, we can define the length of segment AX from the fence to the ladder base as 'x'. Then the length of the ladder to the top of the fence is found using the Pythagorean theorem to be ...
BX = √(x² +8²)
The remaining length of the ladder is the hypotenuse of a triangle similar to ∆BAX. The scale factor is DA/AX = 4/x, so the length of the remaining ladder is ...
CB = (4/x)BX = (4/x)√(x² +8²)
The total ladder length is the sum of its parts:
CX = CB +BX
CX = (4/x)√(x² +8²) +√(x² +8²)
CX = (1 +4/x)√(x² +8²)
The minimum length will be that associated with the value of x that makes the derivative of CX be zero. The second attachment shows the derivative of the total length function in terms of generic distances DA=d and BA=h. For this problem, where (d, h) = (4, 8), the derivative is ...
CX' = (1+4/x)x/√(x² +8²) -(4/x²)√(x² +8²)
Expressing this over a common denominator, we have ...
CX' = (x³ -4·8²)/(x²√(x²+8²))
This is zero when ...
x³ -4·8² = 0 ⇒ x = 4∛4 ≈ 6.3496
Using this value in the ladder length formula above, we find the length of the ladder to be ...
CX = (1 +4/6.3496)√(6.3496² +8²) ≈ 16.64775
The length of the shortest ladder is about 16.65 feet.
how do i get the x-intercept and
y-intercept to this equation?
Answer: The height of fir tree is 9 meters and the height of pine tree is 12 meters.
Step-by-step explanation:
Given : The combined height of one fir tree and one pine tree = 21 meters.
Since, the height of 4 fir trees stacked on top of each other is 24 meters taller than one pine tree.
Let x be the height of fir tree and y be the height of pine tree.
Then we get the following equations:
Adding (1) and (2) we get
Substitute the value of x in (1), we get
Hence, the height of fir tree is 9 meters and the height of pine tree is 12 meters.
A 180
B 120
C 45
D 60
Answer:
60° .
.
.
.
....................
.
.