Question

С11=-8, с13=7. Знайти с12. -½ 0,5 ½ -0,5

Answer 1

Ответ:

-0, 5

Объяснение:

с13=с12+d=c11+2d

Тогда 7=-8+2d

2d=15

d=7,5

C12=c11+d=-8+7,5=-0, 5

Answer 2

To find the value of C12, we can use the formula for the determinants of a 3x3 matrix:

| A B C | | D E F | | G H I |

The determinant of this matrix is given by: det = AEI + BFG + CDH - CEG - BDI - AFH

We are given the values for C11, C13, and the matrix:

C11 = -8 C13 = 7

| -1/2 0.5 | | 1/2 -0.5 |

Now, we need to form the matrix with these known values and the unknown C12, and calculate its determinant. Setting up the matrix:

| -1/2 C12 0.5 | | 1/2 -0.5 7 |

The determinant is:

det = (-1/2 * -0.5 * 7) + (C12 * 0.5 * 1/2) + (0.5 * 1 * 7) - (0.5 * C12 * -1/2) - (-0.5 * 0.5 * 7) - (-1/2 * 1 * 7)

Now, let's solve for C12:

det = (1/4 * 7) + (C12 * 1/4) + (7/2) - (C12 * 1/4) - (7/4) - (-7/2)

det = 7/4 + 7/2 - 7/4

det = 7/2

Thus, the determinant of the matrix is 7/2. To find C12, we can use the formula:

C12 = det / E

C12 = (7/2) / -0.5

C12 = -7/2 * -2

C12 = 7

Therefore, C12 = 7.