Find the inverse of the following matrix without using a calculator 1-1 2 -3 2 1 0 4 - 25

18  -(17/3)   (5/3)

25  (25/3)  (7/3)

4    (4/3)     (1/3)

Step-by-step explanation:

You can solve this problem by using the Gauss-Jordan method.

You have the original matrix and then the Identity matrix.

So:

Original              Identity

1 -1 2                    1 0 0

-3 2 1                   0 1 0

0 4 -25                0 0 1

By the Gauss-Jordan method, in the original place you will have the identity and in the place that the identity currently is you will have the inverse matrix:

So, let's start by setting the first row element to 0 in the second and the third line.

The first row element of the third line is already at zero, so no changes there. In the second line, we need to do:

L2 = L2 + 3L1

So now we have the following matrixes.

1 -1 2        |            1 0 0

0 -1 7       |            3 1 0        

0  4 -25   |            0 0 1

Now we need the element in the second line, second row to be 1. So we do:

L2 = -L2

1 -1 2        |            1 0 0

0 1 -7       |            -3 -1 0        

0  4 -25   |            0 0 1

Now, in the second row, we need to make the elements at the first and third line being zero. So, we have the following operations:

L1 = L1 + L2

L3 = L3 - 4L2

Now our matrixes are:

1 0 -5       |            -2 -1 0

0 1 -7       |            -3 -1 0        

0 0 3       |            12 4 1

Now we need the element in the third line, third row being one. So we do:

L3 = -L3

1 0 -5       |            -2  -1     0

0 1 -7       |            -3  -1      0        

0 0 1       |            4    (4/3) (1/3)

Now, in the third row, we need the elements in the first and second line being zero. So we do:

L1 = L1 + 5L3

L2 = L2 + 7L3

So we have:

1 0 0 |       18  -(17/3)   (5/3)

0 1 0 |       25  (25/3)  (7/3)

0 0 1 |       4    (4/3)     (1/3)

So the inverse matrix is:

18  -(17/3)   (5/3)

25  (25/3)  (7/3)

4    (4/3)     (1/3)

(sin 42)/31. = sinx)/37

sinx = 37 (sin42)/31

= 37× 0.66/31 = 0.787

x= 51.9

other angle opposite to y = 180-51.9-42

= 180- 93.9 =86.1

so

sin42)/31 = sin 86.1)/y

0.021 = 0.997 /y

y= 0.997/0.021 =47.47

pentagon

step-by-step explanation:

the coordinates   a(5, -2), b(3,-1),c(-4,-4) d(-3,8) and e(-1,4) forms the vertices of the polygon when they are connected in order.

in order to classify that which polygon is it with the given coordinates, first count the number of vertices and then count the number of sides it can make with these vertices.

since, the given coordinates have five vertices, therefore, it will make five sides. moreover, pentagon is regular in nature therefore it will be convex.

now, a polygon with five sides is known as pentagon, therefore, the given polygon is the pentagon.