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2 years ago

Find the inner product for (7, 2) * (0, -2) and state whether the vectors are perpendicular.

Mathematics

2 answers:

Kryger [21]2 years ago

5 0

Answer:

a) -4, no

Step-by-step explanation:

a•b = (x1 × x2) + (y1 × y2)

= (7 × 0) + (2 × -2)

= 0 - 4

= -4

Hence they are not Perpendicular

Andrews [41]2 years ago

3 0

Answer: A

Step-by-step explanation:

To find the inner product of two vectors (a,b) and (c,d) you would use the equation (a * c) + (b * d)

So for (7,2) and (0,-2) the inner product would be

(7 * 0) + (2 * -2)

= 4

The vectors are only perpendicular when the inner product is equal to 0. Since it is equal to -4 in this case, the vectors are not perpendicular.

A -4; no

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On a particular game show, there are 8 covered buckets and 2 of them contain a ball.

kobusy [5.1K]

Answer:

0.2143 = 21.43% probability that a contestant wins the game if he/she gets to select 4 of the buckets.

Step-by-step explanation:

The buckets are chosen without replacement, which means that the hypergeometric distribution is used to solve this question.

Hypergeometric distribution:

The probability of x sucesses is given by the following formula:

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

In which:

x is the number of sucesses.

N is the size of the population.

n is the size of the sample.

k is the total number of desired outcomes.

Combinations formula:

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

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

In this question:

8 covered buckets, so N = 8.

4 buckets are selected, so n = 4.

2 contain a ball, which means that k = 2.

Find the probability that a contestant wins the game if he/she gets to select 4 of the buckets.

This is P(X = 2). So

$P(X = x) = h(x,N,n,k) = \frac{C_{k,x}*C_{N-k,n-x}}{C_{N,n}}$

$P(X = 2) = h(2,8,4,2) = \frac{C_{2,2}*C_{6,2}}{C_{8,2}} = 0.2143$

0.2143 = 21.43% probability that a contestant wins the game if he/she gets to select 4 of the buckets.

7 0

2 years ago

Find the percent decrease.Round to the nearest percent. From 97 to 75

damaskus [11]

Answer:

Step-by-step explanation:

Decrease = 97 - 75 = 22

Percentage of decrease=

$=\frac{22}{97}*100$

= 22.68

= 23%

4 0

3 years ago

Need help with a algebra question thanks!

otez555 [7]

It's the first one. If you need any help with graphs, I suggest going on desmos.com

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2 years ago

I need help! Really bad a math.

Alex17521 [72]

Answer:

-72

Step-by-step explanation:

Substitute -4 in the equation

h(-4) = -20 + 13(-4)

h(-4) = -20 + -52

h(-4) = -72

-72 is the final answer

8 0

2 years ago

Read 2 more answers

Cable Strength: A group of engineers developed a new design for a steel cable. They need to estimate the amount of weight the ca

KatRina [158]

Answer:

95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

Step-by-step explanation:

We are given that the engineers take a random sample of 45 cables and apply weights to each of them until they break. The mean breaking weight for the 45 cables is 768.2 lb. The standard deviation of the breaking weight for the sample is 15.1 lb.

Since, in the question it is not specified that how much confidence interval has be constructed; so we assume to be constructing of 95% confidence interval.

Firstly, the Pivotal quantity for 95% confidence interval for the population mean is given by;

P.Q. = $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, $\bar X$ = sample mean breaking weight = 768.2 lb

s = sample standard deviation = 15.1 lb

n = sample of cables = 45

$\mu$ = population mean breaking strength

Here for constructing 95% confidence interval we have used One-sample t test statistics as we don't know about population standard deviation.

So, 95% confidence interval for the population mean, $\mu$ is ;

P(-2.02 < $t_4_4$ < 2.02) = 0.95 {As the critical value of t at 44 degree

of freedom are -2.02 & 2.02 with P = 2.5%}

P(-2.02 < $\frac{\bar X-\mu}{\frac{s}{\sqrt{n} } }$ < 2.02) = 0.95

P( $-2.02 \times {\frac{s}{\sqrt{n} } }$ < ${\bar X-\mu}$ < $2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

P( $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ < $\mu$ < $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ) = 0.95

95% confidence interval for $\mu$ = [ $\bar X-2.02 \times {\frac{s}{\sqrt{n} } }$ , $\bar X+2.02 \times {\frac{s}{\sqrt{n} } }$ ]

= [ $768.2-2.02 \times {\frac{15.1}{\sqrt{45} } }$ , $768.2+2.02 \times {\frac{15.1}{\sqrt{45} } }$ ]

= [763.65 lb , 772.75 lb]

Therefore, 95% confidence interval for the mean breaking strength of the new steel cable is [763.65 lb , 772.75 lb].

3 0

3 years ago