2. Derek is an HVAC technician. He worked 30 hours and made $600. How much per hour does Derek make?

Show that if X is a geometric random variable with parameter p, then

Answer:

$\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}=-\frac{p ln p}{1-p}$

Step-by-step explanation:

The geometric distribution represents "the number of failures before you get a success in a series of Bernoulli trials. This discrete probability distribution is represented by the probability density function:"

$P(X=x)=(1-p)^{x-1} p$

Let X the random variable that measures the number os trials until the first success, we know that X follows this distribution:

$X\sim Geo (1-p)$

In order to find the expected value E(1/X) we need to find this sum:

$E(X)=\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}$

Lets consider the following series:

$\sum_{k=1}^{\infty} b^{k-1}$

And let's assume that this series is a power series with b a number between (0,1). If we apply integration of this series we have this:

$\int_{0}^b \sum_{k=1}^{\infty} r^{k-1}=\sum_{k=1}^{\infty} \int_{0}^b r^{k-1} dt=\sum_{k=1}^{\infty} \frac{b^k}{k}$ (a)

On the last step we assume that $0\leq r\leq b$ and $\sum_{k=1}^{\infty} r^{k-1}=\frac{1}{1-r}$ , then the integral on the left part of equation (a) would be 1. And we have:

$\int_{0}^b \frac{1}{1-r}dr=-ln(1-b)$

And for the next step we have:

$\sum_{k=1}^{\infty} \frac{b^{k-1}}{k}=\frac{1}{b}\sum_{k=1}^{\infty}\frac{b^k}{k}=-\frac{ln(1-b)}{b}$

And with this we have the requiered proof.

And since $b=1-p$ we have that:

$\sum_{k=1}^{\infty} \frac{p(1-p)^{k-1}}{k}=-\frac{p ln p}{1-p}$

4 0

3 years ago

A

g100num [7]

Answer:

A

Step-by-step explanation:

7 0

3 years ago

Pls someone pls help me with this question pls

Mice21 [21]

9514 1404 393

Answer:

A

Step-by-step explanation:

The Pythagorean triple (8, 15, 17) is often seen in algebra and geometry problems. You recognize it as choice A, so you know that is a right triangle.

__

A spreadsheet or graphing calculator can perform the tedium of comparing the sum of squares of the shorter sides to the square of the longer side. The attachment shows a spreadsheet used for that purpose. It identifies the triple (8, 15, 17) as the sides of a right triangle.

5 0

3 years ago

How do you write 3.25 in simplest form

dedylja [7]

3.25 would be 3 1/4 because,

Step 1: You would rewrite the decimal number as a fraction with 1 in the denominator. So, 3.25 = 3.24/1

Step 2: Multiply it by 1 to eliminate 2 decimals places, so multiply the top and bottom by 10^2 = 100
3.25/1 x 100/100 = 325/100
Step 3: Now you find the greatest common factor, also known as GCF, of 325 and 100 if it exits then you reduce the fraction by dividing both numerator and denominator by it. GCF = 25
3.25/100 divided by 25/25 = 13/4
Now you would simplify it to make a proper fraction getting your answer
3 1/4
Does that make sense?

7 0

3 years ago

Read 2 more answers

Let f be a linear function such that f(2) =5 and f(6) = -1. find an equation for f(x).

astra-53 [7]

Using f(x) = y, we know that a graph of the function contains the (x,y) points (2,5) and (6,-1). first find the slope of that line,
m = (y2 - y1)/(x2 - x1) ⇒ -6/4⇒-3/2

then using either point (I'll use the first one) solve for b in y = mx + b.
5 = (-3/2)(2) + b⇒ 5 = -3 + b⇒ 8 = b.

So y = (-3/2)x + 8 ⇒ f(x) = (-3/2)x + 8.

6 0

3 years ago