Answer:
a) 
b) 
c)
![Var(X)=E(X^2)-[E(X)]^2= \frac{1}{2}(e^2 -1) -(e-1)^2 = 0.242](https://tex.z-dn.net/?f=Var%28X%29%3DE%28X%5E2%29-%5BE%28X%29%5D%5E2%3D%20%5Cfrac%7B1%7D%7B2%7D%28e%5E2%20-1%29%20-%28e-1%29%5E2%20%3D%200.242)
Step-by-step explanation:
a) what must the value of C be so that f(x) is a probability density function?
In order to be a probability function we need this condition:

And solving the left part of the integral we have:

, so then 
b) find P(X<2)
We can find this probability on this way using the density function:

c) find E(X) and Var(X)
We can find the expected value on this way:
In order to find the Var(X) we need to find the second moment given by:
And now we can use the following definition:
![Var(X)=E(X^2)-[E(X)]^2= \frac{1}{2}(e^2 -1) -(e-1)^2 = 0.242](https://tex.z-dn.net/?f=Var%28X%29%3DE%28X%5E2%29-%5BE%28X%29%5D%5E2%3D%20%5Cfrac%7B1%7D%7B2%7D%28e%5E2%20-1%29%20-%28e-1%29%5E2%20%3D%200.242)
The median score on the test is 79
Answer:
The diagonal is irrational because it is a product of a rational and an irrational number
Step-by-step explanation:
The options are not given. However, the question is still answerable.
Given
Shape: Square
Length: Rational
Since the side length is said to be rational, I'll answer the question based on whether the diagonal is rational or not.
Having said that:
The diagonal (d) of a square with side length (l) is calculated using Pythagoras theorem.


Take positive square root of both sides

Split:


Recall that the side length (l) is rational.
However,
is irrational.
So, the product of l and
will be irrational
Hence:
The diagonal is irrational
The answer of this question is 4
Our three numbers are...
3 3/10 = 3.3
3.1
3 1/4 = 3.25
So, if we order those from least to greatest, we have...
3.1, 3.25, 3.3
which, in the forms given, is...
3.1, 3-1/4, 3-3/10