Question 4

12 points

How Did I Do?

Format:

• Remember: Möbius does not check your method, and matrix

computations are fiddly. Make sure to check your answers

carefully before submitting.

• If your answer is a vector, enter it as a column vector using the

vector/matrix palette tool.

a.

Find d such that det A = 0, where

7 0 5

2

d 0

4

-1 3

A =

d =

ab

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sin (a)

Ə

f

əx

8

a/nb.

Now, and for the remainder of this question, instead

set d = 12, so

7 0

2

5

12 0

4-1 3,

Calculate the matrix of cofactors for the matrix A.

A =

matrix of cofactors=

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96

sin (a)

f

Əx

∞

α/nC.

d.

Use the information above to find the inverse matrix

A-1, employing the method of cofactors. (This part

still uses that d = 12.)

A-1 =

ab

A

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sin (a)

ə

f

dx

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8

a