Dear Sir:

I try to learn to use the linear algebra in maple.
I try to compute the following matrices.

restart;
assume(a>0,b>0,c>0);
with(LinearAlgebra):
M:=Matrix([[a, 0],[0, b]]);
K:=Matrix([[c,-c],[-c,c]]);
V:=Eigenvectors(K,M);
X:=V[2];
Multiply(Multiply(X^%T,M),X);

I expect that the final result should be the indentity
matrix. However, it does not produce what I expect.
Please give me some advice to get the identity matrix.

Thank you.