Add compiled files

Author: rgaiacs

_episodes/01-first-session.md

@@ -1,5 +1,5 @@
 ---
-title: Objects
+title: First session with SageMath
 teaching: 30
 exercises: 0
 questions:
@@ -8,8 +8,8 @@ objectives:
 - "..."
 ---
 
-The rest of the lesson should be written as a normal RMarkdown file. You can
-include chunk for codes, just like you'd normally do.
+Lesson text
+
 
 
 ~~~
@@ -25,6 +25,22 @@ include chunk for codes, just like you'd normally do.
 {: .output}
 
 
+
+
+~~~
+matrix([[1,2], [3,4]])^(-1)
+~~~
+{: .source .python}
+
+
+
+~~~
+[  -2    1]
+[ 3/2 -1/2]
+~~~
+{: .output}
+
+
 Output with error message:
 
 
@@ -36,7 +52,7 @@ x[10]
 ~~~
 ---------------------------------------------------------------------------
 TypeError Traceback (most recent call last)
-<ipython-input-2-084faa554d6d> in <module>()
+<ipython-input-3-084faa554d6d> in <module>()
 ----> 1 x[Integer(10)]
 
 TypeError: 'sage.symbolic.expression.Expression' object does not support indexing
@@ -52,7 +68,7 @@ plot(sin, (0,10))
 
 
 
-![png](../02-objects_files/02-objects_5_0.png)
+![png](../01-introduction_files/01-introduction_6_0.png)
 
 
 For the challenges

_episodes/02-objects.md renamed to _episodes/01-introduction.md

@@ -0,0 +1,163 @@
+---
+title: Multiply a matrix and a vector
+teaching: 30
+exercises: 0
+questions:
+- "..."
+objectives:
+- "..."
+---
+Let us define the 3 x 3 minus-identity matrix
+
+
+~~~
+A = matrix([[-1,0,0], [0,-1,0], [0,0,-1]])
+A
+~~~
+{: .source .python}
+
+
+
+~~~
+[-1  0  0]
+[ 0 -1  0]
+[ 0  0 -1]
+~~~
+{: .output}
+
+
+Or simply
+
+
+~~~
+A = -identity_matrix(3)
+A
+~~~
+{: .source .python}
+
+
+
+~~~
+[-1  0  0]
+[ 0 -1  0]
+[ 0  0 -1]
+~~~
+{: .output}
+
+
+Define vector `v` to be the vector with coordinates `x`, `y`, `z`
+
+
+~~~
+v = vector([x, y, z])
+~~~
+{: .source .python}
+
+~~~
+---------------------------------------------------------------------------
+NameError Traceback (most recent call last)
+<ipython-input-3-74f33ececb47> in <module>()
+----> 1 v = vector([x, y, z])
+
+NameError: name 'y' is not defined
+~~~
+{: .error}
+Didn't work... We need to define `y` (and `z`) as symbolic variables. Only `x` is defined by default when you launch Sage!
+
+
+~~~
+x, y, z = SR.var("x y z")
+~~~
+{: .source .python}
+
+
+~~~
+v = vector([x, y, z])
+v
+~~~
+{: .source .python}
+
+
+
+~~~
+(x, y, z)
+~~~
+{: .output}
+
+
+Multiply matrix and vector using `*`
+
+
+~~~
+A * v
+~~~
+{: .source .python}
+
+
+
+~~~
+(-x, -y, -z)
+~~~
+{: .output}
+
+
+
+
+~~~
+v.subs(x=1, y=0, z=3)
+~~~
+{: .source .python}
+
+
+
+~~~
+(1, 0, 3)
+~~~
+{: .output}
+
+
+
+
+~~~
+A * v.subs(x=1, y=0, z=3)
+~~~
+{: .source .python}
+
+
+
+~~~
+(-1, 0, -3)
+~~~
+{: .output}
+
+
+
+
+~~~
+A * v
+~~~
+{: .source .python}
+
+
+
+~~~
+(-x, -y, -z)
+~~~
+{: .output}
+
+
+
+
+~~~
+_.subs(x=1, y=0, z=3)
+~~~
+{: .source .python}
+
+
+
+~~~
+(-1, 0, -3)
+~~~
+{: .output}
+
+