1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Setler79 [48]
3 years ago
9

I need help with these problems

Mathematics
1 answer:
ivanzaharov [21]3 years ago
4 0
What kid of math is this?
You might be interested in
Simplify the following expression as much as possible 4^10 divided by 4^10 . 7^0
nikklg [1K]

Answer:

  • 1

Step-by-step explanation:

<u>Simplify</u>

  • 4^10 divided by 4^10 . 7^0
  • 4^10/(4^10*7^0) =
  • 4^10/4^10 =
  • 1
8 0
3 years ago
Read 2 more answers
Solve this equation. (4w-28)+(11w+13)=180
Kitty [74]
Solve for w by simplifying both sides of the equation, then isolating the variable.

w=13
7 0
3 years ago
Let X and Y be discrete random variables. Let E[X] and var[X] be the expected value and variance, respectively, of a random vari
Ulleksa [173]

Answer:

(a)E[X+Y]=E[X]+E[Y]

(b)Var(X+Y)=Var(X)+Var(Y)

Step-by-step explanation:

Let X and Y be discrete random variables and E(X) and Var(X) are the Expected Values and Variance of X respectively.

(a)We want to show that E[X + Y ] = E[X] + E[Y ].

When we have two random variables instead of one, we consider their joint distribution function.

For a function f(X,Y) of discrete variables X and Y, we can define

E[f(X,Y)]=\sum_{x,y}f(x,y)\cdot P(X=x, Y=y).

Since f(X,Y)=X+Y

E[X+Y]=\sum_{x,y}(x+y)P(X=x,Y=y)\\=\sum_{x,y}xP(X=x,Y=y)+\sum_{x,y}yP(X=x,Y=y).

Let us look at the first of these sums.

\sum_{x,y}xP(X=x,Y=y)\\=\sum_{x}x\sum_{y}P(X=x,Y=y)\\\text{Taking Marginal distribution of x}\\=\sum_{x}xP(X=x)=E[X].

Similarly,

\sum_{x,y}yP(X=x,Y=y)\\=\sum_{y}y\sum_{x}P(X=x,Y=y)\\\text{Taking Marginal distribution of y}\\=\sum_{y}yP(Y=y)=E[Y].

Combining these two gives the formula:

\sum_{x,y}xP(X=x,Y=y)+\sum_{x,y}yP(X=x,Y=y) =E(X)+E(Y)

Therefore:

E[X+Y]=E[X]+E[Y] \text{  as required.}

(b)We  want to show that if X and Y are independent random variables, then:

Var(X+Y)=Var(X)+Var(Y)

By definition of Variance, we have that:

Var(X+Y)=E(X+Y-E[X+Y]^2)

=E[(X-\mu_X  +Y- \mu_Y)^2]\\=E[(X-\mu_X)^2  +(Y- \mu_Y)^2+2(X-\mu_X)(Y- \mu_Y)]\\$Since we have shown that expectation is linear$\\=E(X-\mu_X)^2  +E(Y- \mu_Y)^2+2E(X-\mu_X)(Y- \mu_Y)]\\=E[(X-E(X)]^2  +E[Y- E(Y)]^2+2Cov (X,Y)

Since X and Y are independent, Cov(X,Y)=0

=Var(X)+Var(Y)

Therefore as required:

Var(X+Y)=Var(X)+Var(Y)

7 0
3 years ago
5 Points
Simora [160]

Answer: the answer is indeed (4,8)

Step-by-step explanation:

4 0
3 years ago
Please help with this question picture attached ASAP please
olga nikolaevna [1]

1 : 1.71 : 2.43

Step-by-step explanation:

What divided by 7= 1?

7/7 = 1

So use that answer for the other two dolls.

12/7 = 1.71

17/7 = 2.43

1 : 1.71 : 2.43

Have the same ratio as

7 : 12 : 17

5 0
2 years ago
Other questions:
  • Systems of equations that has two points (-10,6)
    11·1 answer
  • There is a total of 1,500 people in the town of Markston. Only 55% of them voted during the town's elections this year. How many
    5·2 answers
  • Please help asap please!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!1
    14·1 answer
  • Help me..... I think it's 18.
    15·1 answer
  • Eleanor deposits 20% of the money that she earns each week in a savings account. If Eleanor earns $85 each week, how much money
    14·2 answers
  • Can anyone help with this please !!!!
    14·1 answer
  • As you can see from the graph, 48% of people questioned chose summer as their favorite season. If 200 people were questioned, ho
    13·2 answers
  • Help ASAP this is do in 10 mins
    8·1 answer
  • What is the sum of (-2)+(-2)
    6·2 answers
  • Evaluate 36 = (x + 9) when x<br> =<br> 3.<br> o<br> A. 3<br> B. 12<br> C. 4.<br> D. 21<br> SUB
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!