1 | initial version |

This is not an answer, but I need more room for my text.

I think that what Shu wants is the following :
#! /usr/bin/sage -python
# -*- coding: utf8 -*-

```
from sage.all import *
var('x,y')
T = (x+y,x*y) # (1)
print T.diff() # (2)
```

But the execution of that code finishes on :

```
AttributeError: 'tuple' object has no attribute 'diff'
```

Thus the question is : how to modify the line (1) in order the line (2) to produce that answer :

```
[(x, y) |--> y (x, y) |--> x]
[(x, y) |--> 1 (x, y) |--> 1]
```

2 | No.2 Revision |

This is not an answer, but I need more room for my text.

I think that what Shu wants is the following ~~:
#! /usr/bin/sage -python
# -~~:*- coding: utf8 -*-

```
#! /usr/bin/sage -python
# -*- coding: utf8 -*-
from sage.all import *
var('x,y')
T = (x+y,x*y) # (1)
print T.diff() # (2)
```

But the execution of that code finishes on :

```
AttributeError: 'tuple' object has no attribute 'diff'
```

Thus the question is : how to modify the line (1) in order the line (2) to produce that answer :

```
[(x, y) |--> y (x, y) |--> x]
[(x, y) |--> 1 (x, y) |--> 1]
```

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