Math  /  Algebra

Question\begin{tabular}{|l|l|l|l|l|l|l|l|l|l|l|l|l|} \hline 1 & 2 & 3 & 4 & 5 & 6 & 7 & 8 & 9 & 10 & 11 & 12 & 13 \\ \hline & & & & & & & & & & & & \\ \hline \end{tabular}
Circle the correct answer 1) If A=[2103]A=\left[\begin{array}{cc}2 & 1 \\ 0 & -3\end{array}\right] and p(x)=x23x+1p(x)=x^{2}-3 x+1, then p(A)=p(A)= a) [10014]\left[\begin{array}{cc}-1 & 0 \\ 0 & 14\end{array}\right] b) [14019]\left[\begin{array}{cc}-1 & -4 \\ 0 & 19\end{array}\right] c) [2103]\left[\begin{array}{cc}2 & 1 \\ 0 & -3\end{array}\right] d) 2103\left|\begin{array}{cc}2 & 1 \\ 0 & -3\end{array}\right| e) [13016]\left[\begin{array}{cc}1 & -3 \\ 0 & 16\end{array}\right] 2) Let A=[301211],B=[1102],C=[112315]A=\left[\begin{array}{cc}3 & 0 \\ -1 & 2 \\ 1 & 1\end{array}\right], B=\left[\begin{array}{cc}1 & -1 \\ 0 & 2\end{array}\right], C=\left[\begin{array}{ccc}1 & -1 & 2 \\ 3 & 1 & 5\end{array}\right]. Then (A+C7)B=\left(A+C^{7}\right) B= a) [422839]\left[\begin{array}{cc}4 & 2 \\ -2 & 8 \\ 3 & 9\end{array}\right] b) [332839]\left[\begin{array}{cc}3 & 3 \\ -2 & 8 \\ 3 & 9\end{array}\right] c) [242839]\left[\begin{array}{cc}2 & 4 \\ -2 & 8 \\ 3 & 9\end{array}\right] d) [512839]\left[\begin{array}{cc}5 & 1 \\ -2 & 8 \\ 3 & 9\end{array}\right] e) [422839]\left[\begin{array}{cc}4 & 2 \\ -2 & 8 \\ 3 & 9\end{array}\right] 3) The values of aa such that the matrix A=[2b+ca2b+2c0523c18]A=\left[\begin{array}{ccc}2 & b+c & a-2 b+2 c \\ 0 & -5 & -2 \\ 3 & c-1 & 8\end{array}\right] is symmetric are a) a=9a=-9 b) a=11a=11 c) a=5a=-5 d) a=1a=-1 e) a=7a=7 4) If a matrix AA satisfies A2+AI=0A^{2}+A-I=0, then A1=A^{-1}= a) AIA-I b) A+IA+I c) IAI-A d) IA-I-A e) AA 5) If A=[1201]A=\left[\begin{array}{cc}1 & -2 \\ 0 & 1\end{array}\right] and B=tr(A)AATB=\operatorname{tr}(A) \cdot A A^{T}, then det(B)=\operatorname{det}(B)= a) 400 b) 36 c) 4 d) 1 e) 0 6) If abcdefghi=6\left|\begin{array}{lll}a & b & c \\ d & e & f \\ g & h & i\end{array}\right|=-6, then abcdefg4dh4ei4f=\left|\begin{array}{ccc}a & b & c \\ d & e & f \\ g-4 d & h-4 e & i-4 f\end{array}\right|=  a) 24 b) 24\begin{array}{ll}\text { a) } 24 & \text { b) }-24\end{array} b) -24 c) 30 d) -30 e) 4 7) The value of aa such that the system 6x(a2+15)y=0-6 x-\left(a^{2}+15\right) y=0 x+(a+1)y=0x+(a+1) y=0 has only the trivial solution is a) a2a \neq 2 b) a=3a=3 c) a3a \neq 3 d) α=2\alpha=2 e) a=1a=1 Page 1 of 2

Studdy Solution
Find a a such that the system has only the trivial solution.
The system is:
6x(a2+15)y=0 -6x - (a^2 + 15)y = 0 x+(a+1)y=0 x + (a+1)y = 0
For the system to have only the trivial solution, the determinant of the coefficient matrix must be non-zero:
det[6(a2+15)1(a+1)]=6(a+1)+(a2+15) \det \begin{bmatrix} -6 & -(a^2 + 15) \\ 1 & (a+1) \end{bmatrix} = -6(a+1) + (a^2 + 15)
Set the determinant to zero:
6(a+1)+a2+15=0 -6(a+1) + a^2 + 15 = 0
a26a+9=0 a^2 - 6a + 9 = 0
(a3)2=0 (a-3)^2 = 0
Thus, a=3 a = 3 .
The correct answer is option b) a=3 a = 3 .

View Full Solution - Free
Was this helpful?

Studdy solves anything!

banner

Start learning now

Download Studdy AI Tutor now. Learn with ease and get all help you need to be successful at school.

ParentsInfluencer programContactPolicyTerms
TwitterInstagramFacebookTikTokDiscord