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3 years ago

Simplify without using the calculator or the sin tables.

Mathematics

1 answer:

katovenus [111]3 years ago

7 0

Answer:

1/8

Step-by-step explanation:

sin²(π/8) − cos⁴(3π/8)

Use power reduction formulas:

1/2 (1 − cos(2×π/8)) − 1/8 (3 + 4 cos(2×3π/8) + cos(4×3π/8))

Simplify:

1/2 (1 − cos(π/4)) − 1/8 (3 + 4 cos(3π/4) + cos(3π/2))

1/2 (1 − √2/2) − 1/8 (3 + 4 (-√2/2) + 0)

1/2 − √2/4 − 1/8 (3 − 2√2)

1/2 − √2/4 − 3/8 +√2/4

1/2 − 3/8

1/8

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A toy maker claims his best product has an average lifespan of exactly 14 years. A skeptical quality control specialist asks for

slamgirl [31]

Answer:

interval = [17.3948 , 20.6052]

Step-by-step explanation:

given,

random sample (n) = 45

average product lifespan = 19 years

standard deviation = 4 years

confidence interval of 99 % = ?

we know,

t* = qt(1.99/2 + 44 ) = qt(0.995,44)

t* = 2.692

so,

interval

$x = 19 \pm t* \times (\dfrac{s}{\sqrt{n}})$

$x = 19 \pm 2.692 \times (\dfrac{4}{\sqrt{45}})$

$x = 19 \pm 2.692 \times 0.5963$

$x = 19 \pm 1.6052$

interval = [19 - 1.6052 , 19 + 1.6052]

interval = [17.3948 , 20.6052]

4 0

3 years ago

Find the slope of the line throgh each pair of points

svlad2 [7]

Answer:

19/24

Step-by-step explanation:

slope = rise/run = (y1 - y2) / (x1 - x2)

s = (19 - 0) / (8 - -16)

s = 19/24

4 0

3 years ago

You are situated 300 feet from the base of Tower Glitz Plaza watching an external elevator descend down the side of the building

nordsb [41]

Answer:

18.66 ft/s

Step-by-step explanation:

The distance between you and the elevator is given by:

$h=\sqrt{x^2+y^2}$

The rate of change for the distance between you and the elevator is given by:

$\frac{dh}{dt}=\frac{dh}{dy}*\frac{dy}{dt}$

$-16=\frac{dh}{dy}*\frac{dy}{dt}$

$\frac{dh}{dy}=\frac{d}{dy} (\sqrt{x^2+y^2})\\$

Applying the chain rule:

$u=x^2+y^2\\\frac{dh}{dy}=\frac{d\sqrt u}{du} *\frac{du}{dy}\\\frac{dh}{dy}=\frac{1}{2\sqrt u} *2y\\\frac{dh}{dy}=\frac{y}{\sqrt {(x^2+y^2)}}$

Therefore, at x=300 and y = 500, dy/dt is:

$-16=\frac{y}{\sqrt {(x^2+y^2)}}*\frac{dy}{dt}\\-16=\frac{500}{\sqrt {(300^2+500^2)}}*\frac{dy}{dt}\\\frac{dy}{dt}=-18.66\ ft/s$

The elevator is descending at 18.66 ft/s.

7 0

3 years ago

A national survey indicated that 30% of adults conduct their banking online. It also found that 40% are under the age of 50. and

Svet_ta [14]

Answer:

Step-by-step explanation:

Hello!

I'll express all the given percentages as probabilities:

Given the events:

Banking online (Bo)

Under the age of 50 (<50)

P(Bo)= 0.30

P(<50)= 0.40

P(Bo ∩ <50)= 0.25

1) What percentage of adults do not conduct their banking online?

The event "adults that do not conduct their baking online" is the complement of the event "adults that conduct their baking online" Symbolically $Bo^c$

P( $Bo^c$ )= 1 - P(Bo)= 1 - 0.30 = 0.70

2) What type of probability is 25%?

The probability P(Bo ∩ <50)= 0.25 is a joint probability, it indicates the intersection between both events.

3) Construct a contingency table showing all joint and marginal probabilities.

Check attachment.

4) What is the probability that an individual conducts banking online given that the individual is under the age of 50?

Symbolically:

P(Bo/<50)= <u> P(Bo ∩ <50) </u> = <u> 0.25 </u> = 0.625

P(<50) 0.40

I hope it helps!

4 0

3 years ago

If a triangle has 2 60 degree angles, what kind of triangle is it?

alexira [117]

Answer:

equilateral

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Simplify without using the calculator or the sin tables.​

Simplify without using the calculator or the sin tables.