If a ball is dropped, how long does it take to fall 60.0 m?
2 answers:
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Answer:
95.15%
Step-by-step explanation:
We have that the mean (m) is equal to 20, the standard deviation (sd) 3
They ask us for P (x <25)
For this, the first thing is to calculate z, which is given by the following equation:
z = (x - m) / sd
We have all these values, replacing we have:
z = (25 - 20) / (3)
z = 1.66
With the normal distribution table (attached), we have that at that value, the probability is:
P (z <1.66) = 0.9515
Which means that the probability that it arrives before 25 minutes is 95.15%
Answer:
f(x) = 1.5x - 0.5x
Step-by-step explanation:
The function of the pattern represented by the pentagonal numbers is the sum of three triangular numbers.
The triangular number general formula
x (x + 1) / 2
For example,
The sequence
1, 3, 6, 10
*
* * *
* * * * * *
* , * *, * * *, * * * *
_____________________________
The pentagonal numbers
The sequence:
1, 5, 12, 22, 35
As shown in the picture can be divided into three triangles
Triangle 2
x (x + 1) / 2
Triangle 1 and 3 (they are triangles one unit smaller than 2)
n (n + 1) / 2
n= x-1
Replacing n
(x-1) ((x-1) + 1) / 2
(x-1) (x) / 2
(x-1) x / 2
______________
Function represents the pattern
Triangle 2 + (Triangle 1 + Triangle 3)
Triangle 1 = Triangle 3
So then,
Triangle 2 + 2* Triangle 1
x (x +1) /2 + 2* (x -1) x/2
Rearranging
0.5 x (x +1) + x(x -1)
0.5x^2 + 0.5x + x^2 -x
(0.5 x^2 + x^2) + (0.5x -x )
1.5 x^2 - 0.5 x
______
