# Informatics1-2017/HW6

## Getting the program

Use one of the following from home:

• install Octave, free for all platforms
• using putty log in to leibniz, start octave with the octave command
• run octave from the computer lab

## How to hand in

Just send a text file with the commands to the usual email address.

### Large matrix

• Create the following matrix using the least characters you can:
```1 2 2 2 2 2 2 2 2 2
2 2 2 2 2 2 2 2 2 2
2 2 3 2 2 2 2 2 2 2
2 2 2 4 2 2 2 2 2 2
2 2 2 2 5 2 2 2 2 2
2 2 2 2 2 6 2 2 2 2
2 2 2 2 2 2 7 2 2 2
2 2 2 2 2 2 2 8 2 2
2 2 2 2 2 2 2 2 9 2
2 2 2 2 2 2 2 2 2 10
```
• Same as before:
``` 0  1  0  0  0  0  0  0  0
-1  0  1  0  0  0  0  0  0
0 -1  0  1  0  0  0  0  0
0  0 -1  0  1  0  0  0  0
0  0  0 -1  0  1  0  0  0
0  0  0  0 -1  0  1  0  0
0  0  0  0  0 -1  0  1  0
0  0  0  0  0  0 -1  0  1
0  0  0  0  0  0  0 -1  0
```
• Chessboard
```  1  -1   1  -1   1
-1   1  -1   1  -1
1  -1   1  -1   1
-1   1  -1   1  -1
1  -1   1  -1   1
```

### Function on matrices

Write a function that applies the function 2sin2x + 1 to every element of a given matrix.

### Part of a matrix

Write a function that separates a 5x5 matrix into a 2x5 matrix with the 2nd and 4th row, and a 3x5 with the 1st, 3rd, 5th.

### Part of a matrix function

Combine the previous two so that the function applies the 2sin2x + 1 function to both new matrices.

### Every second column

Write a function that outputs the matrix with every second column skipped in the input matrix. (Help, size can help with the dimension of the matrix.)

### Applying a function to elements

Write a function that applies the function 2sin2x + 1 to every second column of a matrix.

### Tests

When the task is to write a function test (call) the function as well.