Question

hey some help here ...

Answer 1

how do i do this
system of equations

Answer 2

use the "equation" button :P

Answer 3

^^^ thats my leg+foot getting ready to kick something :P

Answer 4

There are two ways to do cases. The one you probably want is:

```
\(
y=
\begin{cases}
x^2 & \text{ if } x>0 \\
\varnothing & \text{ if } x= 0\\
-x^2 & \text{ if } x<0
\end{cases}
\)
```
\(
y=
\begin{cases}
x^2 & \text{ if } x>0 \\
\varnothing & \text{ if } x= 0\\
-x^2 & \text{ if } x<0
\end{cases}
\)

However, you can also just use a matrix and make the { manually.

```
\(
y=
\left\{\begin{matrix}
x^2 & \text{ if } x>0 \\
\varnothing & \text{ if } x= 0\\
-x^2 & \text{ if } x<0
\end{matrix}\right.
\)
```
\(
y=
\left\{\begin{matrix}
x^2 & \text{ if } x>0 \\
\varnothing & \text{ if } x= 0\\
-x^2 & \text{ if } x<0
\end{matrix}\right.
\)

Answer 5

You may notice a slight difference in spacing. This has to do with differences in how they are constructed by the math package. So if you want the wider spacing, you need to use the matrix.

Answer 6

thanks :)

Answer 7

trying...
\[f(x)=\begin{cases} 1-x& \text{if}~x<-1\\ 2&\text{if}~x=-1\\ x^2-1& \text{if} ~x>-1 \end{cases}\]

Answer 8

working good^^

Answer 9

Yah, and \le and \ge also come in handy for piecewise stuff.

Answer 10

A (cheep) way to get wider spacing [too wide some might say]
is to just put in some blank lines
```
\[
\begin{cases}
\text{blahh} \\
\\
\text{blah} \\
\\
\text{blah}
\end{cases}
\]
```
\[
\begin{cases}
\text{blahh} \\
\\
\text{blah} \\
\\
\text{blah}
\end{cases}
\]

Answer 11

A matrix also puts in more border space between the elements on the horizontal. That would take adding spaces all over the cases, which makes the matrix simpler in that one instance. All of that is why I said cases is usually what people want.

As for the line height, you have a lot more control with that. You can tell it to add to the space between:
```
\[
\begin{cases}
\text{blahh} \\[2pt]
\text{blah} \\[4pt]
\text{blahh} \\[6pt]
\text{blahh} \\[8pt]
\text{blah}
\end{cases}
\]
```
\[
\begin{cases}
\text{blahh} \\[2pt]
\text{blah} \\[4pt]
\text{blahh} \\[6pt]
\text{blahh} \\[8pt]
\text{blah}
\end{cases}
\]

Answer 12

can you show an example using \le and \ge :)

Answer 13

Those are <= and >=

\(
f(x)=\begin{cases}
x^2 &; x\le0\\[2pt]
\dfrac{1}{x} &; x < 0
\end{cases}
\) or \(
f(x)=\begin{cases}
x^2 &; x\ge0\\[2pt]
\dfrac{1}{x} &; x < 0
\end{cases}
\)

```
\(
f(x)=\begin{cases}
x^2 &; x\le0\\[2pt]
\dfrac{1}{x} &; x < 0
\end{cases}
\) or \(
f(x)=\begin{cases}
x^2 &; x\ge0\\[2pt]
\dfrac{1}{x} &; x < 0
\end{cases}
\)
```

As I am sure you know, that is pretty common in piecewise equations.

Answer 14

oh of course i know those
you got me there i thought you meant something else
i have used those several times already if not various times lol
thanks though :)