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1 year ago

14

How many arrangements of three letter can be formed from the letters of the word MATH if anyletter will not be used more than on

ce?

1 answer:

Mariulka [41]1 year ago

7 0

Combinations = n! / (n - r)! r!

$C\text{ = }\frac{n!}{(n-r)!\text{ r!}}\text{ }$

In this case:

n = 4

r = 3

Combinations = 4! /(4-3)! 3! = 24/(1)(6) = 24/6 = 4

Answer:

4 arrangements

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Internet providers: In a survey of 935 homeowners with high-speed Internet, the average monthly cost of a high-speed Internet pl

BlackZzzverrR [31]

Answer:

68% of plans cost between $62.16 and $86.52.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

68% of the measures are within 1 standard deviation of the mean.

95% of the measures are within 2 standard deviation of the mean.

99.7% of the measures are within 3 standard deviations of the mean.

In this problem, we have that:

Mean: 74.34

Standard deviation: 12.18

Bell-shaped is the same as normally distributed.

Estimate the number of plans that cost between $62.16 and $86.52.

62.16 is one standard deviation below the mean.

86.52 is one standard deviation above the mean.

By the Empirical rule, 68% of the measures are within 1 standard deviation of the mean.

So

68% of plans cost between $62.16 and $86.52.

7 0

3 years ago

How is this solved using trig identities (sum/difference)?

GenaCL600 [577]

FIRST PART
We need to find sin α, cos α, and cos β, tan β
α and β is located on third quadrant, sin α, cos α, and sin β, cos β are negative

Determine ratio of ∠α
Use the help of right triangle figure to find the ratio
tan α = 5/12
side in front of the angle/ side adjacent to the angle = 5/12
Draw the figure, see image attached

Using pythagorean theorem, we find the length of the hypotenuse is 13
sin α = side in front of the angle / hypotenuse
sin α = -12/13

cos α = side adjacent to the angle / hypotenuse
cos α = -5/13

Determine ratio of ∠β
sin β = -1/2
sin β = sin 210° (third quadrant)
β = 210°

$cos \beta = -\frac{1}{2} \sqrt{3}$

$tan \beta= \frac{1}{3} \sqrt{3}$

SECOND PART
Solve the questions
Find sin (α + β)
sin (α + β) = sin α cos β + cos α sin β
$sin( \alpha + \beta )=(- \frac{12}{13} )( -\frac{1}{2} \sqrt{3})+( -\frac{5}{13} )( -\frac{1}{2} )$
$sin( \alpha + \beta )=(\frac{12}{26}\sqrt{3})+( \frac{5}{26} )$
$sin( \alpha + \beta )=(\frac{5+12\sqrt{3}}{26})$

Find cos (α - β)
cos (α - β) = cos α cos β + sin α sin β
$cos( \alpha + \beta )=(- \frac{5}{13} )( -\frac{1}{2} \sqrt{3})+( -\frac{12}{13} )( -\frac{1}{2} )$
$cos( \alpha + \beta )=(\frac{5}{26} \sqrt{3})+( \frac{12}{26} )$
$cos( \alpha + \beta )=(\frac{5\sqrt{3}+12}{26} )$

Find tan (α - β)
$tan( \alpha - \beta )= \frac{ tan \alpha-tan \beta }{1+tan \alpha tan \beta }$
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{1}{2} \sqrt{3} }{1+(\frac{5}{12}) ( \frac{1}{2} \sqrt{3})}$

Simplify the denominator
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{1}{2} \sqrt{3} }{1+(\frac{5\sqrt{3}}{24})}$
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{1}{2} \sqrt{3} }{ \frac{24+5\sqrt{3}}{24} }$

Simplify the numerator
$tan( \alpha - \beta )= \frac{ \frac{5}{12} - \frac{6}{12} \sqrt{3} }{ \frac{24+5\sqrt{3}}{24} }$
$tan( \alpha - \beta )= \frac{ \frac{5-6\sqrt{3}}{12} }{ \frac{24+5\sqrt{3}}{24} }$

Simplify the fraction
$tan( \alpha - \beta )= (\frac{5-6\sqrt{3}}{12} })({ \frac{24}{24+5\sqrt{3}})$
$tan( \alpha - \beta )= \frac{10-12\sqrt{3} }{ 24+5\sqrt{3}}$

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3 years ago

Simplify the expression: 1/1+cot^2x

Art [367]

When you simplify the expression 1/1+cot^2x the final product is C. sin^2 (x).

Hope this helps!

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2 years ago

Simplify (6x2 − 3 − 5x3) − (4x3 + 2x2 − 8).

mezya [45]

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(9 - 15) - (16 - 8)
(-6) - (8)
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3 years ago

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A recipe for salad dressing calls for 3 tablespoons of oil for every 2 tablespoons of vinegar. The line represents the relations

pochemuha

Answer:

3:2, 3 to 2

Step-by-step explanation:

4 0

3 years ago