# Zheng

Popular questions and responses by Zheng
1. ## Math

Find the $2 \times 2$ matrix $\bold{A}$ such that $\bold{A} \begin{pmatrix} 1 \\ 0 \end{pmatrix} = \begin{pmatrix} 1 \\ 2 \end{pmatrix}$ and $\bold{A} \begin{pmatrix} 0 \\ 1 \end{pmatrix} = \begin{pmatrix} -7 \\ 4 \end{pmatrix}.$ Regular: Find the 2 x

2. ## Precalculus

Latex: The vector $\begin{pmatrix} k \\ 2 \end{pmatrix}$ is orthogonal to the vector $\begin{pmatrix} 3 \\ 5 \end{pmatrix}$. Find $k$. Regular: The vector , is orthogonal to the vector . Find k. I can't seem to figure it out, I thought k would be 10/3

3. ## Precalculus

Let $\mathcal{G}$ be the graph of the parametric equations \begin{align*} x &= \cos(4t),\\ y &= \sin(6t). \end{align*}What is the length of the smallest interval $I$ such that the graph of these equations for all $t\in I$ produces the entire graph

4. ## Precalculus

Let $\mathcal{G}$ be the graph of the parametric equations \begin{align*} x &= \cos(4t),\\ y &= \sin(6t). \end{align*}What is the length of the smallest interval $I$ such that the graph of these equations for all $t\in I$ produces the entire graph

5. ## Precal

Find the $2 \times 2$ matrix $\bold{A}$ such that $\bold{A} \begin{pmatrix} 1 \\ 0 \end{pmatrix} = \begin{pmatrix} 1 \\ 2 \end{pmatrix}$ and $\bold{A} \begin{pmatrix} 0 \\ 1 \end{pmatrix} = \begin{pmatrix} -7 \\ 4 \end{pmatrix}.$

6. ## Math

Find the $2 \times 2$ matrix $\bold{A}$ such that $\bold{A} \begin{pmatrix} 1 \\ 0 \end{pmatrix} = \begin{pmatrix} 1 \\ 2 \end{pmatrix}$ and $\bold{A} \begin{pmatrix} 0 \\ 1 \end{pmatrix} = \begin{pmatrix} -7 \\ 4 \end{pmatrix}.$

7. ## Precalculus

Compute the distance between the parallel lines given by $\begin{pmatrix} 1 \\ 4 \end{pmatrix} + t \begin{pmatrix} 4 \\ 3 \end{pmatrix}$ and $\begin{pmatrix} -5 \\ 6 \end{pmatrix} + s \begin{pmatrix} 4 \\ 3 \end{pmatrix}.$

8. ## Precalculus

The vector $\begin{pmatrix} k \\ 2 \end{pmatrix}$ is orthogonal to the vector $\begin{pmatrix} 3 \\ 5 \end{pmatrix}$. Find $k$. I thought the answer should be 10/4/

9. ## Precalculus

(a) Suppose $x$ and $y$ are points on the unit circle such that the line through $x$ and $y$ intersects the real axis. Show that if $z$ is the point where this line intersects the real axis, then $z = \dfrac{x+y}{xy+1}$. (b) Let $Q_1 Q_2 \dotsb Q_{18}$ be

1. ## Math

My bad! Thanks for the help! I was able to figure out the latex problem accordingly :)

posted on February 26, 2017
2. ## math

I don't know what you are talking about, but the two real roots must be 3/4, and 9.

posted on February 25, 2017
3. ## Precal

I do not know how to solve this, I am struggling, any help would be appreciated!

posted on February 22, 2017
4. ## Precalculus

Thanks!

posted on February 9, 2017
5. ## Precalculus

That answer keeps on coming as wrong, I had gotten that answer earlier. I am not sure what is wrong :(

posted on January 29, 2017