Maths  Matrices
posted by TP .
I'm having trouble with doing this matrix proof
The question is "Given some matrix A has the property A*2=A^1, show that determinant A = 1, i.e A = 1"
I've tried for ages, but I can't seem to do it, this is what I got to
A^2= A^1
A^2 = A^1
A^2 = 1/A
Can someone please help?

The statement isn't true, you have to make additional assumptions. E.g. one could add the condition that all the matrix elements are real. Then A^3 =1 and you know that A must be a real number, so A must be 1.
The condition that the matrix elements are real is sufficient, but not necessary. E.g., take the 2x2 diagonal matrix with exp(2 pi i/3) and
exp(2 pi i/3) on the diagonal.
Respond to this Question
Similar Questions

Math (matrices)
No one answered my matrix question. Let me rephrase: Let A, B, and 0 be 2x2 matrices. Assuming that A is invertible and 0 is all zeroes, what is the inverse of the matrix [A0] [BA] (that is a 4x4 matrix represented as 4 2x2 matrices) … 
math
hi! Im having trouble with this question about matrices the matrix X = (4 2) (2 4) X to the power of two = 2 (10 8 ) or ...(8 10) 4(5 4) ..(4 5) X to the power of three = 2 (56 52) ...(52 56) or 8 (14 13) .......(13 14) and so on... … 
algebradet.
a) Suppose that B is an n ¡Á n matrix, and k is a scalar. Give a formula for det (kB) in terms of det B . b) Show that your formula from (a) is true for all n and for any k. det (kB) = k^n det B This is because the determinant is … 
matrices
Two matrices can be multiplied only if their sizes are compatible. Suppose that U is an m × n matrix, and that V is a p × q matrix. In order for U•V to make sense, what must be true of the dimensions of these matrices? 
MATHSMatrix
For a given square matrix A the predicted values of matrix B are: predicted B=A(A'A)^(1)A'B why is the matrix C=A(A'A)^(1)A' an idempotent and symmetric matrix? 
Math
I have a few questions about TMatrix. In excel, I am suppose to work with powered matrices to construct a weighted T matrix, using a scalar of .7. Does this mean I multiply each of the powered matrices by .7? 
Maths: Algebra Matrices Class 12th
matrix{{0, 1, 1}, {2, 1, 3}, {1, 1, 1}} matrix{{1, 1, x}} matrix{{0}, {1}, {1}}=0 Find the value of x Don't give me the direct answer. Please tell me how to go about this. Draw in your notebook and then solve 
math
This is a matrix question. R is the matrix (3r 1) (s 2s) 1. State, in terms of s and r the determinant of R 2. If r=1/3 and s=4 determine the inverse of R 3.State the pair of r and s not including 0, which would make the matrix R a … 
math
This is a matrix question. R is the matrix (3r 1) (s 2s) 1. State, in terms of s and r the determinant of R 2. If r=1/3 and s=4 determine the inverse of R 3.State the pair of r and s not including 0, which would make the matrix R a … 
maths
2 . Put the following macroeconomic model into matrix format using Y, C and T as the variables and find the determinant of the matrix of coefficients. There is no need to solve the equations. Y = C + I C = a + b (Y – T) T = tY Kindly …