If F = [[1, 2, 3], [0, 1, 4], [5, 6, 0]], what is det(F)? (2021)
Practice Questions
Q1
If F = [[1, 2, 3], [0, 1, 4], [5, 6, 0]], what is det(F)? (2021)
-14
14
0
10
Questions & Step-by-Step Solutions
If F = [[1, 2, 3], [0, 1, 4], [5, 6, 0]], what is det(F)? (2021)
Step 1: Identify the matrix F. F = [[1, 2, 3], [0, 1, 4], [5, 6, 0]].
Step 2: Write the formula for the determinant of a 3x3 matrix: det(F) = a(ei - fh) - b(di - fg) + c(dh - eg), where F = [[a, b, c], [d, e, f], [g, h, i]].
Step 3: Assign values from the matrix to the variables: a = 1, b = 2, c = 3, d = 0, e = 1, f = 4, g = 5, h = 6, i = 0.
Step 4: Calculate the first part: ei - fh = (1*0) - (4*6) = 0 - 24 = -24.
Step 5: Calculate the second part: di - fg = (0*0) - (4*5) = 0 - 20 = -20.
Step 6: Calculate the third part: dh - eg = (0*6) - (1*5) = 0 - 5 = -5.
Step 7: Substitute these values back into the determinant formula: det(F) = 1(-24) - 2(-20) + 3(-5).
Step 9: Calculate the final result: -24 + 40 = 16, then 16 - 15 = 1.
Step 10: Conclude that det(F) = 1.
Determinants of Matrices – The question tests the ability to calculate the determinant of a 3x3 matrix using the cofactor expansion method.
Cofactor Expansion – The solution involves applying the cofactor expansion along the first row of the matrix.
Matrix Multiplication and Addition – Understanding how to perform multiplication and addition of numbers during the determinant calculation is essential.
