Consider the following in respect of two non-singular matrices A...
Consider the following in respect of two non-singular matrices A and B of same order:
1. det(A+B)=detA+detB2.\quad(A+B)^{-1}=A^{-1}+B^{-1}Whichoftheaboveis/arecorrect?
Options
A1 only
B2 only
CBoth 1 and 2
DNeither 1 nor 2
Correct answer
D. Neither 1 nor 2
Step-by-step solution
Non-singular matrix is a matrix whose determinate Value is non-zero.
Let A=\left[1112\right] and B=\left[2112\right]
Here, A and B are non-singular matrix Now from Statement 1:
A+B=[1112]+[2112]=[3224]det(A+B)=12−4=8 Now det (A)=1112=1 and det(B)=2112=3
Now, det(A+B)=4=det(A+B)∴ Statement 1 is wrong.
Now from Statement 2:
(A+B)−1=∣A+B∣1adj(A+B)=81[4−2−23] and A−1=∣A∣1adj(A)=11[2−1−11] and B−1=∣B∣1adj(B)=31[2−1−12] Now, A−1+B−1=[2−1−11]+[323−13−132]=\left[383−43−435\right] \neq(A+B)^{-1}\therefore \quadStatement2iswrong\therefore \quad$ Option (D) is correct.