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Anastaziya [24]
3 years ago
12

Find the inverse of ????−7 −2

Mathematics
1 answer:
Masja [62]3 years ago
6 0

Answer:

A^{-1}=\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}

Step-by-step explanation:

A=\begin{bmatrix}-7 & -2\\ 4 & 1\end{bmatrix}

det\ A=-7\times 1-(-2)\times 4\\\Rightarrow det\ A=1

A^{-1}=\frac{1}{det\ A}\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}\\\Rightarrow A^{-1}=\frac{1}{1}\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}\\\Rightarrow A^{-1}=\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}

\therefore A^{-1}=\begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}

A.A^{-1}=\begin{bmatrix}-7 & -2\\ 4 & 1\end{bmatrix}\times \begin{bmatrix}1 & 2\\ -4 & -7\end{bmatrix}\\\Rightarrow A.A^{-1}=\begin{pmatrix}\left(-7\right)\cdot \:1+\left(-2\right)\left(-4\right)&\left(-7\right)\cdot \:2+\left(-2\right)\left(-7\right)\\ 4\cdot \:1+1\cdot \left(-4\right)&4\cdot \:2+1\cdot \left(-7\right)\end{pmatrix}\\\Rightarrow A.A^{-1}=\begin{pmatrix}1&0\\ 0&1\end{pmatrix}

Hence, confirmed

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Needs answers <br> Will mark brainliest
Elden [556K]

QUESTION 1:

Required angles are: m<2=75°, m<3=75°, m<4= 105°, m<5= 105°, m<6=75°, m<7=75°, m<8=105°

QUESTION 2:

Required angles are: m<1=100° m<2=80°, m<4= 100°, m<5= 100°, m<6=80°, m<7=80°, m<8=100°

Step-by-step explanation:

Question 1:

if m<1 =105°

We need to find the remaining angles.

The corresponding angles of a traversal are same. so the corresponding angle of <1 is angle 5 So, m<5 = 105°

The vertical angles are also equal. so, vertical angle of <1 is <4. So, m<4 = 105°

Vertical angles of m<5 is m<8 so, m<8=105°

m<1 and m<2 are supplementary angles of each other so their sum will be equal to 180°

So, m<1+m<2=180

105+m<2=180

m<2=75°

Same goes for m<3 and m<4 so, m<3 = 75°

m<5 and m<6 so, m<6 = 75°

m<7 and m<8 so, m<7= 75°

So, required angles are: m<2=75°, m<3=75°, m<4= 105°, m<5= 105°, m<6=75°, m<7=75°, m<8=105°

Question No 2

if m<3=80°

We need to find the remaining angles.

The corresponding angles of a traversal are same. so the corresponding angle of <3 is angle 7 So, m<7 = 80°

The vertical angles are also equal. so, vertical angle of <3 is <2. So, m<2 = 80°

The Vertical angle of <7 is <6 so, m<6= 80°.

m<1 and m<2 are supplementary angles of each other so their sum will be equal to 180°

So, m<1+m<2=180

m<1+80=180

m<1=100°

Same goes for m<3 and m<4 so, m<4 = 100°

m<5 and m<6 so, m<5 = 100°

m<7 and m<8 so, m<8= 100°

So, required angles are: m<1=100° m<2=80°, m<4= 100°, m<5= 100°, m<6=80°, m<7=80°, m<8=100°

Keywords: Traversal of parallel lines

Learn more about traversal of parallel lines at:

  • brainly.com/question/1598227
  • brainly.com/question/3227215
  • brainly.com/question/10483199

#learnwithBrainly

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3 years ago
Consider the matrices.<br> What products are defined for these matrices?
pychu [463]

Answer:

Shows how to quickly check if a matrix product is defined and, if it is, how to ... You can use this fact to check quickly whether a given multiplication is defined.

Step-by-step explanation:

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3 years ago
Help me and please explain
k0ka [10]

Answer:

4 attendees

Step-by-step explanation:

we can create and equation (x is the amount of attendees) $8 per attendee at a total of $32 is 8x=32 which you divide on both sides getting x=4 or 4 attendees

4 0
3 years ago
Trying to find volume of a right circular cone.
viva [34]

Volume of the cone is 117.5 π ft³

<u>Step-by-step explanation:</u>

Lateral area of the cone = πrs

s is the slant height = 15 ft

From the above formula, we can find the radius as, 5 ft.

Volume of the cone = π r² h/3

s = √ (5²+ h²)

Squaring on both sides, we will get,

s² = 15² = (5² + h²)

 15² - 5² = h²

225 - 25 = 200 = h²

h = √200 = 14.1 ft

Volume = π × 5² × 14.1  / 3 = 117.5 π ft³

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Find two integers whose sum is -13 and product is 42
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Answer:

they are -6 and -7

Step-by-step explanation:

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