All categories

3 years ago

1. If 3 + 4 =7 , then 7=3+4 what property is this 2. If m

Mathematics

2 answers:

lukranit [14]3 years ago

6 0

Communitive property

AlladinOne [14]3 years ago

3 0

Question 1 demonstrates the Commutative Property.

You might be interested in

What is the solution of the system of equations 2x-5y=11 and -2x+3y=-9

Rainbow [258]

Equation 1:
x = (5y+11)/2
Substitute equation 1 to 2:
-2((5y+11)/2)+ 3y=-9
-2/2 = -1 thus -1(5y+11)

Continue...
-(5y+11)+3y=-9
-5y-11+3y =-9
(-5+3)y= 11-9
-2y = 2
y=-1

Substitute y into equation 1:
x=(5*-1+11)/2
x = 6/2=3

So y=-1 and x =3

6 0

2 years ago

The table below shows a correct representation that 15 pounds (lb) of sugar cost $3:

SIZIF [17.4K]

Answer: True

Step-by-step explanation: There are 15 pounds and 3 dollars. 15 over 3 is $1 for 5 pounds.

4 0

3 years ago

Please help me!!!!! i need full answer.

salantis [7]

Answer:

see explanation

Step-by-step explanation:

Using the sum/ difference → product formula

cos x - cos y = - 2sin( $\frac{x+y}{2}$ )sin ( $\frac{x-y}{2}$ )

sin x - sin y = 2cos ( $\frac{x+y}{2}$ )sin ( $\frac{x-y}{2}$ )

Given

(cosA - cosB)² + (sinA - sinB )²

= [ - 2sin( $\frac{A+B}{2}$ )sin( $\frac{A-B}{2}$ ) ]² + [ 2cos( $\frac{A+B}{2}$ )sin( $\frac{A-B}{2}$ ) ]²

= 4sin² ( $\frac{A+B}{2}$ )sin² ( $\frac{A-B}{2}$ ) + 4cos² ( $\frac{A+B}{2}$ )sin² ( $\frac{A-B}{2}$ )

= 4sin² ( $\frac{A-B}{2}$ )[ sin² ( $\frac{A+B}{2}$ ) + cos² ( $\frac{A+B}{2}$ ) ← sin²x + cos²x = 1

= 4sin² ( $\frac{A-B}{2}$ ) × 1

= 4sin² ( $\frac{A-B}{2}$ ) = right side ⇒ proven

4 0

3 years ago

For a certain river, suppose the drought length Y is the number of consecutive time intervals in which the water supply remains

AnnZ [28]

Answer:

a) There is a 9% probability that a drought lasts exactly 3 intervals.

There is an 85.5% probability that a drought lasts at most 3 intervals.

b)There is a 14.5% probability that the length of a drought exceeds its mean value by at least one standard deviation

Step-by-step explanation:

The geometric distribution is the number of failures expected before you get a success in a series of Bernoulli trials.

It has the following probability density formula:

$f(x) = (1-p)^{x}p$

In which p is the probability of a success.

The mean of the geometric distribution is given by the following formula:

$\mu = \frac{1-p}{p}$

The standard deviation of the geometric distribution is given by the following formula:

$\sigma = \sqrt{\frac{1-p}{p^{2}}$

In this problem, we have that:

$p = 0.383$

$\mu = \frac{1-p}{p} = \frac{1-0.383}{0.383} = 1.61$

$\sigma = \sqrt{\frac{1-p}{p^{2}}} = \sqrt{\frac{1-0.383}{(0.383)^{2}}} = 2.05$

(a) What is the probability that a drought lasts exactly 3 intervals?

This is $f(3)$

$f(x) = (1-p)^{x}p$

$f(3) = (1-0.383)^{3}*(0.383)$

$f(3) = 0.09$

There is a 9% probability that a drought lasts exactly 3 intervals.

At most 3 intervals?

This is $P = f(0) + f(1) + f(2) + f(3)$

$f(x) = (1-p)^{x}p$

$f(0) = (1-0.383)^{0}*(0.383) = 0.383$

$f(1) = (1-0.383)^{1}*(0.383) = 0.236$

$f(2) = (1-0.383)^{2}*(0.383) = 0.146$

Previously in this exercise, we found that $f(3) = 0.09$

$P = f(0) + f(1) + f(2) + f(3) = 0.383 + 0.236 + 0.146 + 0.09 = 0.855$

There is an 85.5% probability that a drought lasts at most 3 intervals.

(b) What is the probability that the length of a drought exceeds its mean value by at least one standard deviation?

This is $P(X \geq \mu+\sigma) = P(X \geq 1.61 + 2.05) = P(X \geq 3.66) = P(X \geq 4)$ .

We are working with discrete data, so 3.66 is rounded up to 4.

Either a drought lasts at least four months, or it lasts at most thee. In a), we found that the probability that it lasts at most 3 months is 0.855. The sum of these probabilities is decimal 1. So:

$P(X \leq 3) + P(X \geq 4) = 1$

$0.855 + P(X \geq 4) = 1$

$P(X \geq 4) = 0.145$

There is a 14.5% probability that the length of a drought exceeds its mean value by at least one standard deviation

8 0

3 years ago

Question 1(Multiple Choice Worth 5 points)

ioda

15/31 is the answer

7 0

3 years ago