Home
Class 12
MATHS
If |(6i,-3i,1),(4,3i,-1),(40,3,i)|=x+iy,...

If `|(6i,-3i,1),(4,3i,-1),(40,3,i)|=x+iy`, then:

A

x=3, y=1

B

x=1,y=3

C

x=0, y=3

D

x=0, y=0

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the determinant of the given matrix: \[ \begin{vmatrix} 6i & -3i & 1 \\ 4 & 3i & -1 \\ 40 & 3 & i \end{vmatrix} \] ### Step 1: Set up the determinant The determinant of a 3x3 matrix can be calculated using the formula: \[ \text{det}(A) = a(ei - fh) - b(di - fg) + c(dh - eg) \] For our matrix: - \( a = 6i, b = -3i, c = 1 \) - \( d = 4, e = 3i, f = -1 \) - \( g = 40, h = 3, i = i \) ### Step 2: Calculate the determinant Now, we will calculate each part of the determinant: 1. **Calculate \( ei - fh \)**: \[ ei = (3i)(i) = 3i^2 = 3(-1) = -3 \] \[ fh = (-1)(3) = -3 \] \[ ei - fh = -3 - (-3) = -3 + 3 = 0 \] 2. **Calculate \( di - fg \)**: \[ di = (4)(i) = 4i \] \[ fg = (-1)(40) = -40 \] \[ di - fg = 4i - (-40) = 4i + 40 \] 3. **Calculate \( dh - eg \)**: \[ dh = (4)(3) = 12 \] \[ eg = (3i)(40) = 120i \] \[ dh - eg = 12 - 120i \] ### Step 3: Substitute back into the determinant formula Now substituting back into the determinant formula: \[ \text{det}(A) = 6i(0) - (-3i)(4i + 40) + 1(12 - 120i) \] \[ = 0 + 3i(4i + 40) + (12 - 120i) \] \[ = 3i(4i) + 3i(40) + 12 - 120i \] \[ = 12i^2 + 120i + 12 - 120i \] \[ = 12(-1) + 12 = -12 + 12 = 0 \] ### Step 4: Conclusion The determinant is \( 0 \). Therefore, we can express this in the form \( x + iy \): \[ 0 = 0 + 0i \] Thus, \( x = 0 \) and \( y = 0 \). ### Final Answer The values of \( x \) and \( y \) are: - \( x = 0 \) - \( y = 0 \)
Promotional Banner