There is 25 coins in a bag, 5 of them are quarters. What is the probability of getting a quarter? Express as all four types of p
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Mean number of errors in each page = 0.01
Mean number of errors in 100 pages = 0.01*100=1
It is possible to use the cumulative distribution function (CMF), but the math is a little more complex, involving the gamma-function. Tables and software are available for that purpose.
Thus it is easier to evaluate with a calculator for the individual cases of k=0,1,2 and 3.
The Poisson distribution has a PMF (probability mass function)
with λ = 1
=>
=>
or
P(k<=3)=0.9810 (to four decimal places)
Mean number of errors in 100 pages = 0.01*100=1
It is possible to use the cumulative distribution function (CMF), but the math is a little more complex, involving the gamma-function. Tables and software are available for that purpose.
Thus it is easier to evaluate with a calculator for the individual cases of k=0,1,2 and 3.
The Poisson distribution has a PMF (probability mass function)
with λ = 1
=>
=>
or
P(k<=3)=0.9810 (to four decimal places)
First let's solve the general case for an isosceles triangle of base 2 and height k. If the triangle is drawn so the base is on the x-axis and the apex is on the y-axis, the equation for the line containing the right side is
y = -k(x-1)
Then a rectangle with x-dimension w will have an area that is the product of this width and the height y = -k((w/2)-1).
area = w(-k(w/2 -1)) = (-k/2)w² +kw
The derivative of area with respect to w will be zero where the area is a maximum:
d(area)/dw = 0 = -kw +k
w = 1 . . . . . . add kw and divide by k
Using the formula for area, we find
area = 1(-k(1/2-1)) = k/2
This value is 1/2 the total area of the triangle we started with.
If the side lengths of your triangle are 8, √80, and √80, the height will be given by the Pythagorean theorem as
h = √((√80)² - (1/2·8)²) = √(80-16) = 8
Your triangle's area will be
triangle area = (1/2)(8)(8) = 32
The maximum area of the inscribed rectangle will be half this value,
16 square units
y = -k(x-1)
Then a rectangle with x-dimension w will have an area that is the product of this width and the height y = -k((w/2)-1).
area = w(-k(w/2 -1)) = (-k/2)w² +kw
The derivative of area with respect to w will be zero where the area is a maximum:
d(area)/dw = 0 = -kw +k
w = 1 . . . . . . add kw and divide by k
Using the formula for area, we find
area = 1(-k(1/2-1)) = k/2
This value is 1/2 the total area of the triangle we started with.
If the side lengths of your triangle are 8, √80, and √80, the height will be given by the Pythagorean theorem as
h = √((√80)² - (1/2·8)²) = √(80-16) = 8
Your triangle's area will be
triangle area = (1/2)(8)(8) = 32
The maximum area of the inscribed rectangle will be half this value,
16 square units