Consider the following statements relating to structural analysis:
1. Flexibility matrix and its transpose are equal.
2. Elements of main diagonal of stiffness matrix are always positive.
3. For unstable structures, coefficients in leading matrix can be negative.
which of these statements is/are CORRECT?
1
1, 2 and 3
2
1 and 2 only
3
2 and 3 only
4
3 only