Math Is Fun Forum

mrpace

Member

Registered: 2012-08-16

Posts: 88

help with matrix problem please

let M be an invertible matrix. If M^3=M, find the possible vales of the determinant of M.

anonimnystefy

Real Member

From: Harlan's World

Registered: 2011-05-23

Posts: 16,049

Re: help with matrix problem please

I would say the answer

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stapel

Member

Registered: 2006-07-22

Posts: 15

Re: help with matrix problem please

let M be an invertible matrix. If M^3=M, find the possible vales of the determinant of M.

Since M is invertible, then there exists a matrix M^(-1) such that M*M^(-1) = M^(-1)*M = I.

What happens if you multiply the given equation, either on the left or on the right, by that inverse matrix? What do you know about the value of the determinant of the right-hand side of the resulting equation?