I am solving an 11×11 matrix in Mathematica. I am facing problem when I try to find the determinant or eigenvalues of this matrix. The error generated shows that the matrix is not square therefore it cannot solve it. But when I manually check the matrix by checking the dimension it gives 11×11 matrix.

Another issue that I am facing is that when I ask the logical question from Mathematica to check whether my matrix is symmetric or not? Mathematica always give false. Whereas, again when I manually check the solution by subtracting the matrix from its transpose, I get a 11×11 null matrix.

So far these things are making me very confused, a help from your end will be highly appreciated. I am also attaching the program with this email.

```
ClearAll("Global`*")
KLC = {{{(47 C55c)/(30 c) + (6 c (b^2 C11c + a^2 C66c) (Pi)^2)/(
35 a^2 b^2) + (C11t/a^2 + C66t/b^2) ft (Pi)^2}, {-((7 C55c)/(
30 c)) + (c (b^2 C11c + a^2 C66c) (Pi)^2)/(
35 a^2 b^2)}, {-((4 C55c)/(3 c)) + (
2 c (b^2 C11c + a^2 C66c) (Pi)^2)/(15 a^2 b^2)}, {2/
35 (-14 C55c +
c^2 (C11c/a^2 + C66c/b^2) (Pi)^2)}, {((6 c (C12c + C66c) +
35 (C12t + C66t) ft) (Pi)^2)/(35 a b)}, {(
c (C12c + C66c) (Pi)^2)/(35 a b)}, {(
2 c (C12c + C66c) (Pi)^2)/(
15 a b)}, {-((2 c^2 (C12c + C66c) (Pi)^2)/(
35 a b))}, {((-22 c C13c + 38 c C55c + 47 C55c ft) (Pi))/(
60 a c) + (3 c (b^2 C11c + a^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^3 b^2)}, {((Pi) (-6 c^2 C11c fb (Pi)^2 +
a^2 (-14 c (C13c + C55c) + 49 C55c fb - (
6 c^2 (C12c + 2 C66c) fb (Pi)^2)/b^2)))/(420 a^3 c)}, {(
2 (C13c + C55c) (Pi))/(
5 a)}}, {{-((7 C55c)/(30 c)) + (
c (b^2 C11c + a^2 C66c) (Pi)^2)/(35 a^2 b^2)}, {(47 C55c)/(
30 c) + (6 c (b^2 C11c + a^2 C66c) (Pi)^2)/(
35 a^2 b^2) + (C11b/a^2 + C66b/b^2) fb (Pi)^2}, {-((4 C55c)/(
3 c)) + (2 c (b^2 C11c + a^2 C66c) (Pi)^2)/(15 a^2 b^2)}, {(
4 C55c)/5 - (2 c^2 (b^2 C11c + a^2 C66c) (Pi)^2)/(
35 a^2 b^2)}, {(c (C12c + C66c) (Pi)^2)/(
35 a b)}, {((6 c (C12c + C66c) + 35 (C12b + C66b) fb) (Pi)^2)/(
35 a b)}, {(2 c (C12c + C66c) (Pi)^2)/(15 a b)}, {(
2 c^2 (C12c + C66c) (Pi)^2)/(35 a b)}, {(
6 c^2 C11c ft (Pi)^3 +
a^2 (Pi) (14 c (C13c + C55c) - 49 C55c ft + (
6 c^2 (C12c + 2 C66c) ft (Pi)^2)/b^2))/(
420 a^3 c)}, {((22 c C13c - 38 c C55c - 47 C55c fb) (Pi))/(
60 a c) - (3 c (b^2 C11c + a^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^3 b^2)}, {-((2 (C13c + C55c) (Pi))/(
5 a))}}, {{-((4 C55c)/(3 c)) + (
2 c (b^2 C11c + a^2 C66c) (Pi)^2)/(
15 a^2 b^2)}, {-((4 C55c)/(3 c)) + (
2 c (b^2 C11c + a^2 C66c) (Pi)^2)/(15 a^2 b^2)}, {(8 C55c)/(
3 c) + 16/15 c (C11c/a^2 + C66c/b^2) (Pi)^2}, {0}, {(
2 c (C12c + C66c) (Pi)^2)/(15 a b)}, {(
2 c (C12c + C66c) (Pi)^2)/(15 a b)}, {(
16 c (C12c + C66c) (Pi)^2)/(15 a b)}, {0}, {(
c^2 C11c ft (Pi)^3 +
a^2 (Pi) (-10 (c (C13c + C55c) + C55c ft) + (
c^2 (C12c + 2 C66c) ft (Pi)^2)/b^2))/(
15 a^3 c)}, {(2 (c (C13c + C55c) + C55c fb) (Pi))/(3 a c) - (
c (b^2 C11c + a^2 (C12c + 2 C66c)) fb (Pi)^3)/(
15 a^3 b^2)}, {0}}, {{2/
35 (-14 C55c + c^2 (C11c/a^2 + C66c/b^2) (Pi)^2)}, {(4 C55c)/
5 - (2 c^2 (b^2 C11c + a^2 C66c) (Pi)^2)/(
35 a^2 b^2)}, {0}, {8/
105 c (21 C55c + 2 c^2 (C11c/a^2 + C66c/b^2) (Pi)^2)}, {(
2 c^2 (C12c + C66c) (Pi)^2)/(
35 a b)}, {-((2 c^2 (C12c + C66c) (Pi)^2)/(35 a b))}, {0}, {-((
16 c^3 (C12c + C66c) (Pi)^2)/(
105 a b))}, {-((2 (2 c (C13c + C55c) + 3 C55c ft) (Pi))/(
15 a)) + (c^2 (b^2 C11c + a^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^3 b^2)}, {-((2 (2 c (C13c + C55c) + 3 C55c fb) (Pi))/(
15 a)) + (c^2 (b^2 C11c + a^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^3 b^2)}, {(8 c (C13c + C55c) (Pi))/(
15 a)}}, {{((6 c (C12c + C66c) + 35 (C12t + C66t) ft) (Pi)^2)/(
35 a b)}, {(c (C12c + C66c) (Pi)^2)/(35 a b)}, {(
2 c (C12c + C66c) (Pi)^2)/(15 a b)}, {(
2 c^2 (C12c + C66c) (Pi)^2)/(
35 a b)}, {(47 C44c)/(30 c) + (
6 c (a^2 C22c + b^2 C66c) (Pi)^2)/(
35 a^2 b^2) + (C22t/b^2 + C66t/a^2) ft (Pi)^2}, {-((7 C44c)/(
30 c)) + (c (a^2 C22c + b^2 C66c) (Pi)^2)/(
35 a^2 b^2)}, {-((4 C44c)/(3 c)) + (
2 c (a^2 C22c + b^2 C66c) (Pi)^2)/(15 a^2 b^2)}, {(4 C44c)/
5 - (2 c^2 (a^2 C22c + b^2 C66c) (Pi)^2)/(
35 a^2 b^2)}, {((-22 c C23c + 38 c C44c + 47 C44c ft) (Pi))/(
60 b c) + (3 c (a^2 C22c + b^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^2 b^3)}, {((Pi) (-6 c^2 C22c fb (Pi)^2 +
b^2 (-14 c (C23c + C44c) + 49 C44c fb - (
6 c^2 (C12c + 2 C66c) fb (Pi)^2)/a^2)))/(420 b^3 c)}, {(
2 (C23c + C44c) (Pi))/(5 b)}}, {{(c (C12c + C66c) (Pi)^2)/(
35 a b)}, {((6 c (C12c + C66c) + 35 (C12b + C66b) fb) (Pi)^2)/(
35 a b)}, {(2 c (C12c + C66c) (Pi)^2)/(
15 a b)}, {-((2 c^2 (C12c + C66c) (Pi)^2)/(
35 a b))}, {-((7 C44c)/(30 c)) + (
c (a^2 C22c + b^2 C66c) (Pi)^2)/(35 a^2 b^2)}, {(47 C44c)/(
30 c) + (6 c (a^2 C22c + b^2 C66c) (Pi)^2)/(
35 a^2 b^2) + (C22b/b^2 + C66b/a^2) fb (Pi)^2}, {-((4 C44c)/(
3 c)) + (2 c (a^2 C22c + b^2 C66c) (Pi)^2)/(15 a^2 b^2)}, {2/
35 (-14 C44c + c^2 (C22c/b^2 + C66c/a^2) (Pi)^2)}, {(
6 c^2 C22c ft (Pi)^3 +
b^2 (Pi) (14 c (C23c + C44c) - 49 C44c ft + (
6 c^2 (C12c + 2 C66c) ft (Pi)^2)/a^2))/(
420 b^3 c)}, {((22 c C23c - 38 c C44c - 47 C44c fb) (Pi))/(
60 b c) - (3 c (a^2 C22c + b^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^2 b^3)}, {-((2 (C23c + C44c) (Pi))/(5 b))}}, {{(
2 c (C12c + C66c) (Pi)^2)/(15 a b)}, {(
2 c (C12c + C66c) (Pi)^2)/(15 a b)}, {(
16 c (C12c + C66c) (Pi)^2)/(
15 a b)}, {0}, {-((4 C44c)/(3 c)) + (
2 c (a^2 C22c + b^2 C66c) (Pi)^2)/(
15 a^2 b^2)}, {-((4 C44c)/(3 c)) + (
2 c (a^2 C22c + b^2 C66c) (Pi)^2)/(15 a^2 b^2)}, {(8 C44c)/(
3 c) + 16/15 c (C22c/b^2 + C66c/a^2) (Pi)^2}, {0}, {(
c^2 C22c ft (Pi)^3 +
b^2 (Pi) (-10 (c (C23c + C44c) + C44c ft) + (
c^2 (C12c + 2 C66c) ft (Pi)^2)/a^2))/(
15 b^3 c)}, {(2 (c (C23c + C44c) + C44c fb) (Pi))/(3 b c) - (
c (a^2 C22c + b^2 (C12c + 2 C66c)) fb (Pi)^3)/(
15 a^2 b^3)}, {0}}, {{-((2 c^2 (C12c + C66c) (Pi)^2)/(
35 a b))}, {(2 c^2 (C12c + C66c) (Pi)^2)/(
35 a b)}, {0}, {-((16 c^3 (C12c + C66c) (Pi)^2)/(105 a b))}, {(
4 C44c)/5 - (2 c^2 (a^2 C22c + b^2 C66c) (Pi)^2)/(
35 a^2 b^2)}, {2/
35 (-14 C44c + c^2 (C22c/b^2 + C66c/a^2) (Pi)^2)}, {0}, {8/
105 c (21 C44c + 2 c^2 (C22c/b^2 + C66c/a^2) (Pi)^2)}, {(
2 (2 c (C23c + C44c) + 3 C44c ft) (Pi))/(15 b) - (
c^2 (a^2 C22c + b^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^2 b^3)}, {(2 (2 c (C23c + C44c) + 3 C44c fb) (Pi))/(
15 b) - (c^2 (a^2 C22c + b^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^2 b^3)}, {-((8 c (C23c + C44c) (Pi))/(
15 b))}}, {{((-22 c C13c + 38 c C55c + 47 C55c ft) (Pi))/(
60 a c) + (3 c (b^2 C11c + a^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^3 b^2)}, {(
6 c^2 C11c ft (Pi)^3 +
a^2 (Pi) (14 c (C13c + C55c) - 49 C55c ft + (
6 c^2 (C12c + 2 C66c) ft (Pi)^2)/b^2))/(420 a^3 c)}, {(
c^2 C11c ft (Pi)^3 +
a^2 (Pi) (-10 (c (C13c + C55c) + C55c ft) + (
c^2 (C12c + 2 C66c) ft (Pi)^2)/b^2))/(
15 a^3 c)}, {-((2 (2 c (C13c + C55c) + 3 C55c ft) (Pi))/(
15 a)) + (c^2 (b^2 C11c + a^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^3 b^2)}, {((-22 c C23c + 38 c C44c + 47 C44c ft) (Pi))/(
60 b c) + (3 c (a^2 C22c + b^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^2 b^3)}, {(
6 c^2 C22c ft (Pi)^3 +
b^2 (Pi) (14 c (C23c + C44c) - 49 C44c ft + (
6 c^2 (C12c + 2 C66c) ft (Pi)^2)/a^2))/(420 b^3 c)}, {(
c^2 C22c ft (Pi)^3 +
b^2 (Pi) (-10 (c (C23c + C44c) + C44c ft) + (
c^2 (C12c + 2 C66c) ft (Pi)^2)/a^2))/(
15 b^3 c)}, {(2 (2 c (C23c + C44c) + 3 C44c ft) (Pi))/(15 b) - (
c^2 (a^2 C22c + b^2 (C12c + 2 C66c)) ft (Pi)^3)/(
35 a^2 b^3)}, {1/(
840 a^4 b^4 c) (980 a^4 b^4 C33c +
7 a^2 b^2 (a^2 (32 c^2 C44c + 47 C44c ft^2 -
4 c (11 C23c ft - 19 C44c ft + 30 ktP)) +
b^2 (32 c^2 C55c + 47 C55c ft^2 -
4 c (11 C13c ft - 19 C55c ft + 30 ktP))) (Pi)^2 +
2 c ft^2 (18 c (b^4 C11c + a^4 C22c +
2 a^2 b^2 (C12c + 2 C66c)) +
35 (b^4 C11t + a^4 C22t +
2 a^2 b^2 (C12t + 2 C66t)) ft) (Pi)^4)}, {1/(
840 a^4 b^4 c) (140 a^4 b^4 C33c -
7 a^2 b^2 (a^2 (8 c^2 C44c - 7 C44c fb ft +
2 c (C23c + C44c) (fb + ft)) +
b^2 (8 c^2 C55c - 7 C55c fb ft +
2 c (C13c + C55c) (fb + ft))) (Pi)^2 -
6 c^2 (b^4 C11c + a^4 C22c +
2 a^2 b^2 (C12c + 2 C66c)) fb ft (Pi)^4)}, {1/
15 (-((20 C33c)/c) + 2 c (C44c/b^2 + C55c/a^2) (Pi)^2 +
3 ((C23c + C44c)/b^2 + (C13c + C55c)/
a^2) ft (Pi)^2)}}, {{((Pi) (-6 c^2 C11c fb (Pi)^2 +
a^2 (-14 c (C13c + C55c) + 49 C55c fb - (
6 c^2 (C12c + 2 C66c) fb (Pi)^2)/b^2)))/(
420 a^3 c)}, {((22 c C13c - 38 c C55c - 47 C55c fb) (Pi))/(
60 a c) - (3 c (b^2 C11c + a^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^3 b^2)}, {(2 (c (C13c + C55c) + C55c fb) (Pi))/(3 a c) - (
c (b^2 C11c + a^2 (C12c + 2 C66c)) fb (Pi)^3)/(
15 a^3 b^2)}, {-((2 (2 c (C13c + C55c) + 3 C55c fb) (Pi))/(
15 a)) + (c^2 (b^2 C11c + a^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^3 b^2)}, {((Pi) (-6 c^2 C22c fb (Pi)^2 +
b^2 (-14 c (C23c + C44c) + 49 C44c fb - (
6 c^2 (C12c + 2 C66c) fb (Pi)^2)/a^2)))/(
420 b^3 c)}, {((22 c C23c - 38 c C44c - 47 C44c fb) (Pi))/(
60 b c) - (3 c (a^2 C22c + b^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^2 b^3)}, {(2 (c (C23c + C44c) + C44c fb) (Pi))/(3 b c) - (
c (a^2 C22c + b^2 (C12c + 2 C66c)) fb (Pi)^3)/(15 a^2 b^3)}, {(
2 (2 c (C23c + C44c) + 3 C44c fb) (Pi))/(15 b) - (
c^2 (a^2 C22c + b^2 (C12c + 2 C66c)) fb (Pi)^3)/(
35 a^2 b^3)}, {1/(
840 a^4 b^4 c) (140 a^4 b^4 C33c -
7 a^2 b^2 (a^2 (8 c^2 C44c - 7 C44c fb ft +
2 c (C23c + C44c) (fb + ft)) +
b^2 (8 c^2 C55c - 7 C55c fb ft +
2 c (C13c + C55c) (fb + ft))) (Pi)^2 -
6 c^2 (b^4 C11c + a^4 C22c +
2 a^2 b^2 (C12c + 2 C66c)) fb ft (Pi)^4)}, {1/(
840 a^4 b^4 c) (980 a^4 b^4 C33c +
7 a^2 b^2 (a^2 (32 c^2 C44c + 47 C44c fb^2 -
4 c (11 C23c fb - 19 C44c fb + 30 ktP)) +
b^2 (32 c^2 C55c + 47 C55c fb^2 -
4 c (11 C13c fb - 19 C55c fb + 30 ktP))) (Pi)^2 +
2 c fb^2 (18 c (b^4 C11c + a^4 C22c +
2 a^2 b^2 (C12c + 2 C66c)) +
35 (b^4 C11b + a^4 C22b +
2 a^2 b^2 (C12b + 2 C66b)) fb) (Pi)^4)}, {1/
15 (-((20 C33c)/c) + 2 c (C44c/b^2 + C55c/a^2) (Pi)^2 +
3 ((C23c + C44c)/b^2 + (C13c + C55c)/a^2) fb (Pi)^2)}}, {{(
2 (C13c + C55c) (Pi))/(
5 a)}, {-((2 (C13c + C55c) (Pi))/(5 a))}, {0}, {(
8 c (C13c + C55c) (Pi))/(15 a)}, {(2 (C23c + C44c) (Pi))/(
5 b)}, {-((2 (C23c + C44c) (Pi))/(5 b))}, {0}, {-((
8 c (C23c + C44c) (Pi))/(15 b))}, {1/
15 (-((20 C33c)/c) + 2 c (C44c/b^2 + C55c/a^2) (Pi)^2 +
3 ((C23c + C44c)/b^2 + (C13c + C55c)/a^2) ft (Pi)^2)}, {1/
15 (-((20 C33c)/c) + 2 c (C44c/b^2 + C55c/a^2) (Pi)^2 +
3 ((C23c + C44c)/b^2 + (C13c + C55c)/a^2) fb (Pi)^2)}, {(
8 C33c)/(3 c) + 16/15 c (C44c/b^2 + C55c/a^2) (Pi)^2}}};
```