Part BCSIR NET June 2025trace-of-a-squared-is-not-the-determinant-square-the-sum-first

Trace of a squared is not the determinant square the sum first

Which of the following polynomials is the characteristic polynomial of a real 2 × 2 matrix A such that trace(A) = 7 and trace $(A^{2}) = 29$ ?

A. $t^{2} + 7 t + 10$
B. $t^{2} - 7 t + 29$
C. $t^{2} - 7 t - 10$
D. $t^{2} - 7 t + 10$ ✓

You have the answer. Trap Analysis is why the other three were written.

Not a worked solution repeated four times — the specific reasoning error each wrong option was built to reward, and why this one tests execution slip.

See pricing

50 are analysed free — try those first.

The trap it tests

Execution slip

The idea was right. The computation was not.

Drill statements like this

Related counterexample: Same characteristic polynomial ⇒ similar

Trace of a squared is not the determinant square the sum first

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