hi i need to know -

how do you find the inverse of matrix B from:

(I+B)^-1=I-B

where I is the identity matrix, and B is a 4x4 square matrix.

B in this case is:

-7 0 0 8

-6 5 -4 5

-4 4 -3 3

-8 0 0 9

thanks to anyone who can help(Handshake)

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- Nov 13th 2007, 10:47 AMsmilermatrices
hi i need to know -

how do you find the inverse of matrix B from:

(I+B)^-1=I-B

where I is the identity matrix, and B is a 4x4 square matrix.

B in this case is:

-7 0 0 8

-6 5 -4 5

-4 4 -3 3

-8 0 0 9

thanks to anyone who can help(Handshake) - Nov 13th 2007, 01:59 PMPeritus
I think there is something wrong with the info because:

(I+B)^-1=I-B

<=> I = (I-B)*(I+B)

<=> I = I + B -B -B^2

<=> I = I - B^2

<=> B^2 = 0

which means that B is nilpotent and therefore not invertible. - Nov 13th 2007, 02:36 PMPlato
As you can see the given information is inconsistent.