Answer:
15 ft
Step-by-step explanation:
This problem can be represented by a right angle triangle, shown in the diagram below.
The distance between Jin and Zoe is the hypotenuse of the triangle, x.
According to Pythagoras theorem,
hyp² = opp² + adj²
Where opp is the opposite side and adjacent is the adjacent side to any angle of consideration (which is not important in this case)
Hence:
x² = 12² + 9²
x² = 144 + 81
x² = 225
Finding the square root:
x = 15 ft
Jin and Zoe are 15 ft apart.
Answer:
The value of x that gives the maximum transmission is 1/√e ≅0.607
Step-by-step explanation:
Lets call f the rate function f. Note that f(x) = k * x^2ln(1/x), where k is a positive constant (this is because f is proportional to the other expression). In order to compute the maximum of f in (0,1), we derivate f, using the product rule.
We need to equalize f' to 0
- k*(2x ln(1/x) - x) = 0 -------- We send k dividing to the other side
- 2x ln(1/x) - x = 0 -------- Now we take the x and move it to the other side
- 2x ln(1/x) = x -- Now, we send 2x dividing (note that x>0, so we can divide)
- ln(1/x) = x/2x = 1/2 ------- we send the natural logarithm as exp
- 1/x = e^(1/2)
- x = 1/e^(1/2) = 1/√e ≅ 0.607
Thus, the value of x that gives the maximum transmission is 1/√e.
A human blinks 6,250,000 times a year.
A seal blinks 1,010 times a year.
