Is the number rational or irrational?

Tamiku [17]

Answer:

Let's assign the variable x to cosA. The expression then becomes x² - 5x + 6. To factorize this we need to find two numbers that have a sum of -5 and a product of 6; these numbers are -2 and -3 so the expression becomes (x - 2)(x - 3). Since we know that x = cosA the final answer is (cosA - 2)(cosA - 3).

5 0

3 years ago

HELPLSPLSPLPSLPSLPSL

babunello [35]

Answer:

25.5

Step-by-step explanation:

first find the area od the rectangle than the triangle.

to find the area count the number of squares and use A=b*h

than do the same for the triangle using A=.5*b*h

15=3*5

10.5=.5*3*7

10.5+15=25.5

3 0

3 years ago

Plz help ill give u brainlyest. <br><br> Also anser a and b

erica [24]

Answer:

A) 4/7 feet

B) 4/7 x 15 = 60/7 or $8\frac{4}{7}$

5 0

3 years ago

A random sample of 49 measurements from one population had a sample mean of 15, with sample standard deviation 5. An independent

kotykmax [81]

Answer:

Comparing the p value with the significance level $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and the difference between the two groups is significantly different.

Step-by-step explanation:

$\bar X_{1}=15$ represent the mean for sample 1

$\bar X_{2}=18$ represent the mean for sample 2

$s_{1}=5$ represent the sample standard deviation for 1

$s_{f}=6$ represent the sample standard deviation for 2

$n_{1}=49$ sample size for the group 2

$n_{2}=64$ sample size for the group 2

$\alpha=0.01$ Significance level provided

t would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the difference in the population means, the system of hypothesis would be:

Null hypothesis: $\mu_{1}-\mu_{2}=0$

Alternative hypothesis: $\mu_{1} - \mu_{2}\neq 0$

We don't have the population standard deviation's, so for this case is better apply a t test to compare means, and the statistic is given by:

$t=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{s^2_{1}}{n_{1}}+\frac{s^2_{2}}{n_{2}}}}$ (1)

And the degrees of freedom are given by $df=n_1 +n_2 -2=49+64-2=111$

t-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

With the info given we can replace in formula (1) like this:

$t=\frac{(15-18)-0}{\sqrt{\frac{5^2}{49}+\frac{6^2}{64}}}}=-2.897$

P value

Since is a bilateral test the p value would be:

$p_v =2*P(t_{111}$

Comparing the p value with the significance level $\alpha=0.01$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and the difference between the two groups is significantly different.

7 0

3 years ago

A player ran 30 yards in a football game. How many feet did the player run?

Bad White [126]

Taking into account the change of units, the player ran 90 feets in the football game.

<h3>Rule of three</h3>

In first place, the rule of three is a way of solving problems of proportionality between three known values and an unknown value, establishing a relationship of proportionality between all of them.

That is, what is intended with it is to find the fourth term of a proportion knowing the other three.

If the relationship between the magnitudes is direct, that is, when one magnitude increases, so does the other (or when one magnitude decreases, so does the other) , the direct rule of three must be applied.

To solve a direct rule of three, the following formula must be followed, being a, b and c known data and x the variable to be calculated:

a ⇒ b

c ⇒ x

So: $x=\frac{cxb}{a}$

The direct rule of three is the rule applied in this case where there is a change of units.

<h3>Change of units</h3>

To perform in this case the conversion of units, you must first know that 1 yard = 3 feets. So, if 3 feets is 1 yard, how many feets equals 30 yards?

1 yard ⇒ 3 feets

30 yards ⇒ x

So: $x=\frac{30 yardsx3 feets}{1 yard}$

Solving:

<u><em>x= 90 feets</em></u>

In summary, the player ran 90 feets in the football game.

Learn more with this example:

<u>brainly.com/question/12482948?referrer=searchResults</u>

8 0

2 years ago