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3 years ago

Please help. A B C D

Mathematics

1 answer:

s344n2d4d5 [400]3 years ago

6 0

Answer:

A. t(x) = 450 - 0.06x

Step-by-step explanation:

The layer which is originally 450 m thick is decreasing by 0.06 m.

450 - 0.06

... per day. x represents days.

0.06x

So,

450 - 0.06x

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Two poles 8m and 13m high

Brilliant_brown [7]

Answer:

13 m

Step-by-step explanation:

<u>The distance x is:</u>

x = √12² + (13 -8)² = √144 + 25 = √169 = 13 m

6 0

3 years ago

Can some one help me ‼ pleasee ‼

marshall27 [118]

Answer:

Step-by-step explanation:

The 2 lines are equal in length. Therefore:-

ST = 21 - 9 = 12

7 0

3 years ago

A data mining routine has been applied to a transaction dataset and has classified 88 records as fraudulent (30 correctly so) an

chubhunter [2.5K]

Answer:

The classification matrix is attached below

Part a

The classification error rate for the records those are truly fraudulent is 65.91%.

Part b

The classification error rate for records that are truly non-fraudulent is 96.64%

Step-by-step explanation:

The classification matrix is obtained as shown below:

The transaction dataset has 30 fraudulent correctly classified records out of 88 records, that is, 30 records are correctly predicted given that an instance is negative.

Also, there would be 88 - 30 = 58 non-fraudulent incorrectly classified records, that is, 58 records are incorrectly predicted given that an instance is positive.

The transaction dataset has 920 non-fraudulent correctly classified records out of 952 records, that is, 920 records are correctly predicted given that an instance is positive.

Also, there would be 952 - 920 = 32 fraudulent incorrectly classified records, that is, 32 records incorrectly predicted given that an instance is negative.

That is,

Predicted value

Active value Fraudulent Non-fraudulent

Fraudlent 30 58

non-fraudulent 32 920

The classification matrix is obtained by using the information related to the transaction data, which is classified into fraudulent records and non-fraudulent records.

The error rate is obtained as shown below:

The error rate is obtained by taking the ratio of $\left( {b + c} \right)(b+c)$ and the total number of records.

The classification matrix is, shown above

The total number of records is, $30 + 58 + 32 + 920 = 1,040$

The error rate is,

$\begin{array}{c}\\{\rm{Error}}\,{\rm{rate}} = \frac{{b + c}}{{{\rm{Total}}}}\\\\ = \frac{{58 + 32}}{{1,040}}\\\\ = \frac{{90}}{{1,040}}\\\\ = 0.0865\\\end{array}$

The percentage is $0.0865 \times 100 = 8.65$

(a)

The classification error rate for the records those are truly fraudulent is obtained by taking the rate ratio of b and $\left( {a + b} \right)(a+b)$ .

The classification error rate for the records those are truly fraudulent is obtained as shown below:

The classification matrix is, shown above and in the attachment

The error rate for truly fraudulent is,

$\begin{array}{c}\\FP = \frac{b}{{a + b}}\\\\ = \frac{{58}}{{30 + 58}}\\\\ = \frac{{58}}{{88}}\\\\ = 0.6591\\\end{array}$

The percentage is, $0.6591 \times 100 = 65.91$

(b)

The classification error rate for records that are truly non-fraudulent is obtained by taking the ratio of d and $\left( {c + d} \right)(c+d)$ .

The classification error rate for records that are truly non-fraudulent is obtained as shown below:

The classification matrix is, shown in the attachment

The error rate for truly non-fraudulent is,

$\begin{array}{c}\\TP = \frac{d}{{c + d}}\\\\ = \frac{{920}}{{32 + 920}}\\\\ = \frac{{920}}{{952}}\\\\ = 0.9664\\\end{array}$

The percentage is, $0.9664 \times 100 = 96.64$

8 0

3 years ago

Solve the system of equations using matrices. x+7y=02x−8y=22 Question 7 (Mandatory) (1 point) Step 1. Find the coefficient matri

Alex Ar [27]

Answer:

x=7

y =-1

Step-by-step explanation:

Given is a system of equations in x and y as

$x+7y=0\\2x-8y =22$

This can be written in matrix form as

Ax = B

$\left[\begin{array}{ccc}1&7\\2&-8\end{array}\right]\left[\begin{array}{ccc}x\\y\end{array}\right] =\left[\begin{array}{ccc}0\\22\end{array}\right]$

Let us find inverse of A

$|A| = -8-14 =-22$

$A^{-1} =\frac{-1}{22} *\left[\begin{array}{ccc}-8&-7\\-2&1\end{array}\right]$

X= A ^(-1) B

x=7, y =-1

4 0

3 years ago

Show that sin( + 180°) + 2 cos( − 360°) − sin( − 180°) = 2x

den301095 [7]

Answer:

Example 1: Change sin 80° cos 130° + cos 80° sin 130° into a trigonometric function in ... Example 2: Verify that cos (180° − x) = − cos x ... Example 7: Verify that sin (360° − x) = − sin x.

8 0

3 years ago