From 07447e3054508d133e026499329baa554772f2dd Mon Sep 17 00:00:00 2001 From: Steven Clontz Date: Fri, 14 Nov 2025 11:07:30 -0600 Subject: [PATCH 1/5] fix so column number appears in non-invertible task --- .vscode/settings.json | 5 +++++ .../linear-algebra/exercises/outcomes/MX/MX2/generator.sage | 1 + source/linear-algebra/exercises/outcomes/MX/MX2/template.xml | 5 ++--- 3 files changed, 8 insertions(+), 3 deletions(-) create mode 100644 .vscode/settings.json diff --git a/.vscode/settings.json b/.vscode/settings.json new file mode 100644 index 000000000..a490b614a --- /dev/null +++ b/.vscode/settings.json @@ -0,0 +1,5 @@ +{ + "githubPullRequests.ignoredPullRequestBranches": [ + "main" + ] +} \ No newline at end of file diff --git a/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage b/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage index c746b4e2d..75950ff0b 100644 --- a/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage +++ b/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage @@ -43,6 +43,7 @@ class Generator(BaseGenerator): "invertible": False, "label": labels[1], "vector_eq": TBIL.VectorEquation(m), + "ordinal": ordinal_string, }] shuffle(matrices) diff --git a/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml b/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml index e91a16524..32177b643 100644 --- a/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml +++ b/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml @@ -54,9 +54,8 @@ N/A

If the matrix is invertible, explain and demonstrate how to find the -{{ordinal}} column of this inverse using a technique that could be -performed without technology (though you may use technology for this -exercise). +{{ordinal}} column of this inverse by solving an appropriate linear system +or vector equation.

From 8c8e67db4ebbcb1221aedafa02b6492bb6c9b1ba Mon Sep 17 00:00:00 2001 From: Steven Clontz Date: Fri, 14 Nov 2025 11:12:56 -0600 Subject: [PATCH 2/5] move column computation before using tech --- .../exercises/outcomes/MX/MX2/template.xml | 20 +++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml b/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml index 32177b643..6ea78888d 100644 --- a/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml +++ b/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml @@ -36,13 +36,19 @@ discussing its corresponding linear transformation.

-If the matrix is invertible, use technology to find its inverse. +If the matrix is invertible, explain and demonstrate how to find the +{{ordinal}} column of this inverse by solving an appropriate linear system +or vector equation.

-Its inverse is {{inverse}}. +Since + +\operatorname{RREF} {{ord_matrix}} = {{ord_rref}} + +the {{ordinal}} column of the inverse is {{ord_col}}. N/A @@ -53,19 +59,13 @@ N/A

-If the matrix is invertible, explain and demonstrate how to find the -{{ordinal}} column of this inverse by solving an appropriate linear system -or vector equation. +If the matrix is invertible, use technology to find its inverse.

-Since - -\operatorname{RREF} {{ord_matrix}} = {{ord_rref}} - -the {{ordinal}} column of the inverse is {{ord_col}}. +Its inverse is {{inverse}}. N/A From 3bac25923fb6ae2e3be4b8adfe87e84592d69e7c Mon Sep 17 00:00:00 2001 From: Steven Clontz Date: Fri, 14 Nov 2025 12:05:36 -0600 Subject: [PATCH 3/5] add info on bijection --- source/linear-algebra/exercises/outcomes/MX/MX2/template.xml | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml b/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml index 6ea78888d..30be28e26 100644 --- a/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml +++ b/source/linear-algebra/exercises/outcomes/MX/MX2/template.xml @@ -25,10 +25,10 @@ discussing its corresponding linear transformation.

-{{label}} is invertible. +{{label}} is invertible because its transformation is bijective. -{{label}} is not invertible. +{{label}} is not invertible because its transformation is not bijective.

From fccb7323bf8ac2a5ab2bbc9d3566f8945ccbb09f Mon Sep 17 00:00:00 2001 From: Drew Lewis Date: Fri, 14 Nov 2025 20:21:29 +0000 Subject: [PATCH 4/5] Spell out ordinals --- source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage b/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage index 75950ff0b..99bdc9b2e 100644 --- a/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage +++ b/source/linear-algebra/exercises/outcomes/MX/MX2/generator.sage @@ -14,7 +14,7 @@ class Generator(BaseGenerator): constants = A*solution m = A.augment(constants, subdivide=True) ordinal = randrange(1,4) - ordinal_string = ["1st", "2nd", "3rd", "4th"][ordinal] + ordinal_string = ["first", "second", "third", "fourth"][ordinal] ord_matrix = A.augment(column_matrix( identity_matrix(4).column(ordinal)), subdivide=True) From 940e018d323ff7bbcd1c6dc7a904b5b1f6e23997 Mon Sep 17 00:00:00 2001 From: Steven Clontz Date: Fri, 14 Nov 2025 20:25:58 +0000 Subject: [PATCH 5/5] remove .vscode file --- .vscode/settings.json | 5 ----- 1 file changed, 5 deletions(-) delete mode 100644 .vscode/settings.json diff --git a/.vscode/settings.json b/.vscode/settings.json deleted file mode 100644 index a490b614a..000000000 --- a/.vscode/settings.json +++ /dev/null @@ -1,5 +0,0 @@ -{ - "githubPullRequests.ignoredPullRequestBranches": [ - "main" - ] -} \ No newline at end of file