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math54-f22:midterm1-sample [2022/10/01 07:40]
pzhou created
math54-f22:midterm1-sample [2026/02/21 14:41] (current)
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 ====== Sample Midterm 1 ====== ====== Sample Midterm 1 ======
-Our midterm will be 50 minutes, hold in discussion session on Monday. The test range is Givental [LA] Ch 1 and Ch 2, and Ch 3 with the concept of basis, linear independence and span. We will have 5 problems, each worth 20 points. +Our midterm will be 50 minutes, hold in discussion session on next Wednesday (Oct 5). The test range is Givental [LA] Ch 1 and Ch 2, and Ch 3 with the concept of basis, linear independence and span. We will have 5 problems, each worth 20 points. 
  
-** Problem 1 ** True or False, please explain your reasoning.  \\ +** Problem 1 ** (20 pts) True or False. If you think it is truegive some explanation; if you think it is false, give a counter-example.  \\ 
-  * Let conic curve $C$ be given by the equation $a x^2 + b xy + cy^2=1$, where $a,b,c$ are real numbers. If $a,b,c$ are all positive, then $C$ must be an ellipse.  +  * Let the conic curve $C$ be given by the equation $a x^2 + b xy + cy^2=1$, where $a,b,c$ are real numbers. If $a,b,c$ are all positive, then $C$ must be an ellipse.  
-  * +  * Let $T: \R^2 \to \R^2$ be a linear transformation. If $T( (1,0)) \neq (0,0)$ and $T( (0,1) ) \neq (0,0)$, then $T$ must be invertible.  
 +  * Let $z_1, \cdots, z_5$ be the roots of polynomial equation $z^5+5z+3=0$, then $z_1+\cdots+z_5=0$.  
 +  * Let $A$ be a 3 by 3 matrix. If $A^2=0$, then $A$ is the zero matrix. 
  
 +** Problem 2 ** (20 pts) 
 +$$ \begin{pmatrix}
 +1 & 1 & 1 \cr
 +0 & 1 & 1 \cr
 +0 & 0 & 1 \cr
 +\end{pmatrix}^2=? $$
  
 +$$ \det \begin{pmatrix}
 +1 & 1 & 1 \cr
 +0 & 2 & 1 \cr
 +0 & 3 & 4 \cr
 +\end{pmatrix}=? $$
 +
 +** Problem 3 ** (20 pts) 
 +Represent the bilinear form $B( (x_1,x_2), (y_1,y_2) ) = 2 x_1(y_1+y_2)$ in $\R^2$ as  the sum $S+A$ of a symmetric and an anti-symmetric ones.
 +
 +** Problem 4 ** (20 pts)  
 +What is the length of the permutation $\begin{pmatrix} 1 & 2 & 3 & 4 \cr 2 & 4 & 3 & 1 \end{pmatrix}$? 
 +
 +** Problem 5 ** (20 pts)  
 +Let $A$ be a size $n$ matrix. Express $\det(adj(A))$ using $\det A$. 
  
  
  
math54-f22/midterm1-sample.1664610011.txt.gz · Last modified: 2026/02/21 14:44 (external edit)