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3 years ago

12

TAn elevator starts at the ground floor and makes 4 stops. The positive numbers stand for going up, and the negative numbers sta

nd for going down. Which expression gives the total number of floors traveled during the 4 stops?

2 answers:

Varvara68 [4.7K]3 years ago

8 0

Answer:

I can answer if u post a pic or at least a link

Step-by-step explanation:

GarryVolchara [31]3 years ago

4 0

Can u send a link? Or at least show da picture first so we can help you

You might be interested in

2) Plot these points on a piece of graph paper. Draw a line to connect each of the pairs indicated. Then, determine which line i

valina [46]

2) longest line is (-1, -3) and (-1, 7)

3) (-1, -3), (-6,2), and (2,4)

5 0

3 years ago

Where does the helix r(t) = cos(πt), sin(πt), t intersect the paraboloid z = x2 + y2? (x, y, z) = What is the angle of intersect

Colt1911 [192]

Answer:

Intersection at (-1, 0, 1).

Angle 0.6 radians

Step-by-step explanation:

The helix r(t) = (cos(πt), sin(πt), t) intersects the paraboloid

z = x2 + y2 when the coordinates (x,y,z)=(cos(πt), sin(πt), t) of the helix satisfy the equation of the paraboloid. That is, when

$\bf (cos(\pi t), sin(\pi t), t)$

But

$\bf cos^2(\pi t)+sin^2(\pi t)=1$

so, the helix intersects the paraboloid when t=1. This is the point

(cos(π), sin(π), 1) = (-1, 0, 1)

The angle of intersection between the helix and the paraboloid is the angle between the tangent vector to the curve and the tangent plane to the paraboloid.

The <em>tangent vector</em> to the helix in t=1 is

r'(t) when t=1

r'(t) = (-πsin(πt), πcos(πt), 1), hence

r'(1) = (0, -π, 1)

A normal vector to the tangent plane of the surface

$\bf z=x^2+y^2$

at the point (-1, 0, 1) is given by

$\bf (\frac{\partial f}{\partial x}(-1,0),\frac{\partial f}{\partial y}(-1,0),-1)$

where

$\bf f(x,y)=x^2+y^2$

since

$\bf \frac{\partial f}{\partial x}=2x,\;\frac{\partial f}{\partial y}=2y$

so, a normal vector to the tangent plane is

(-2,0,-1)

Hence, <em>a vector in the same direction as the projection of the helix's tangent vector (0, -π, 1) onto the tangent plane </em>is given by

$\bf (0,-\pi,1)-((0,-\pi,1)\bullet(-2,0,-1))(-2,0,1)=(0,-\pi,1)-(-2,0,1)=(2,-\pi,0)$

The angle between the tangent vector to the curve and the tangent plane to the paraboloid equals the angle between the tangent vector to the curve and the vector we just found.

But we now

$\bf (2,-\pi,0)\bullet(0,-\pi,1)=\parallel(2,-\pi,0)\parallel\parallel(0,-\pi,1)\parallel cos\theta$

where

$\bf \theta$ = angle between the tangent vector and its projection onto the tangent plane. So

$\bf \pi^2=(\sqrt{4+\pi^2}\sqrt{\pi^2+1})cos\theta\rightarrow cos\theta=\frac{\pi^2}{\sqrt{4+\pi^2}\sqrt{\pi^2+1}}=0.8038$

and

$\bf \theta=arccos(0.8038)=0.6371\;radians$

7 0

3 years ago

yan [13]

The answer should be “93j”

3 0

3 years ago

Read 2 more answers

The Australian sheep dog is a breed renowned for its intelligence and work ethic. It is estimated that 30% of adult Australian s

m_a_m_a [10]

Answer:

0.15% probability that more than 7 of them weigh 65 lb

Step-by-step explanation:

For each dog, there are only two possible outcomes. Either they weigh 65 pounds, or more, or they do not. The probability of a dog weighing 65 pounds or more is independent of other dogs. So we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

30% of adult Australian sheep dogs weigh 65 pounds or more.

This means that $p = 0.3$

Sample of 10 adults dogs.

This means that $n = 10$

What is the probability that more than 7 of them weigh 65 lb

This is

$P(X > 7) = P(X = 8) + P(X = 9) + P(X = 10)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 8) = C_{10,8}.(0.3)^{8}.(0.7)^{2} = 0.0014$

$P(X = 9) = C_{10,9}.(0.3)^{9}.(0.7)^{1} = 0.0001$

$P(X = 10) = C_{10,10}.(0.3)^{10}.(0.7)^{0} \cong 0$

$P(X > 7) = P(X = 8) + P(X = 9) + P(X = 10) = 0.0014 + 0.0001 + 0 = 0.0015$

0.15% probability that more than 7 of them weigh 65 lb

7 0

3 years ago

Mary and Roberto bought identical backpacks at different stores. Mary's backpack originally cost $65 and was discounted 25%. Rob

mihalych1998 [28]

Answer:

Mary's

Step-by-step explanation:

8 0

4 years ago