Graham puts $20 in his piggy bank every week. at the end of 39 weeks, he adds $100 to the piggy bank money and decides to do the
1 answer:
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Answer:
14.86 knots.
Step-by-step explanation:
<em>Given that:</em>
The boats leave the port at noon.
Speed of boat 1 = 12 knots due east
Speed of boat 2 = 8 knots due south
At 2 pm:
Distance traveled by boat 1 = 24 units due east
Distance traveled by boat 2 = 16 units due south
Now, speed of boat 1 changes to 9 knots:
At 3 pm:
Distance traveled by boat 1 = 24 + 9= 33 units due east
Distance traveled by boat 2 = 16+8 = 24 units due south
Now, speed of boat 1 changes to 8+7 = 15 knots
At 5 pm:
Distance traveled by boat 1 = 33 + 2 9= 51 units due east
Distance traveled by boat 2 = 24 + 2 15 = 54 units due south
Now, the situation of distance traveled can be seen by the attached right angled .
O is the port and A is the location of boat 1
B is the location of boat 2.
Using pythagorean theorem:
so, the total distance between the two boats is 74.28 units.
Change in distance per hour =
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.