Linear Algebra Drills
The procedures, until they are fast
MA201 teaches each of these once, against one example, and moves on. This is the volume — thirty-three procedures from a dot product to a condition number, on questions generated fresh that never run out. Each stays green only while your recent answers hold.
- Modules
- 9
- Drills
- 33
- Build steps
- 0
- Time
- ~7h
Walk out able to
Reduce a matrix, read its rank, find both eigenvalues of a $2 \times 2$ and project onto a line — without stopping to rebuild the method first.
What you drill
Vectors and systems
Norms, dot products, spans, elimination, the three verdicts.
Matrices and determinants
Products, inverses, the plane maps, 2×2 and 3×3 by hand.
Spaces, rank, eigenvalues
Independence, coordinates, pivots, subspaces, eigenvalues.
Orthogonality and fitting
Projection, Gram–Schmidt, normal equations, singular values.
The pitch
What you practise, and what you leave with
Not an artifact — a set of reflexes. Thirty-three procedures that are each either current or not, and a rail that says which.
You will practise
- Norms, dot products, spans, elimination
- Matrix products, inverses, determinants
- Rank, the four subspaces, eigenvalues
- Projection, Gram–Schmidt, least squares
Afterwards you can
- Reduce and read a rank off a matrix
- Find both eigenvalues of a 2×2
- Project, and name the residual
- Read a condition number for what it costs
Modules
9 modules, 34 items
Lessons explain one idea. Drills repeat it until it sticks. Build steps make something that exists afterwards.
- 1
Vectors and their lengths
~42 minMeasure, dot and classify a pair of vectors without rebuilding the formula first.
- LessonWhat this project is for4 min
- DrillMeasure a vector three ways8 min
- DrillDot two vectors8 min
- DrillRead the angle off the sign11 min
- DrillName what they span11 min
- 2
Solve and read a system
~47 minEliminate, back-substitute, and call the verdict before solving anything.
- DrillSolve a 2×2 system14 min
- DrillClear the entry under a pivot8 min
- DrillBack-substitute upward14 min
- DrillOne, none, or infinitely many11 min
- 3
Matrices as maps
~41 minApply, compose and invert a 2×2, and recall the map each one performs.
- DrillApply a matrix to a vector8 min
- DrillMultiply two matrices8 min
- DrillName the transformation11 min
- DrillInvert a 2×214 min
- 4
Spaces and independence
~36 minTest a subset, spot a redundant direction, and read coordinates off a basis.
- DrillRun the subspace test11 min
- DrillIndependent, or redundant11 min
- DrillFind the coordinates14 min
- 5
Rank and the four subspaces
~42 minCount pivots, deduce the count you were not given, and place each subspace.
- DrillCount the pivots20 min
- DrillRank plus nullity11 min
- DrillPlace the subspace11 min
- 6
Determinants
~50 minEvaluate at 2×2 and 3×3, and carry a determinant through an operation.
- DrillTake a 2×2 determinant8 min
- DrillTake a 3×3 determinant20 min
- DrillTrack a row operation11 min
- DrillUse a determinant identity11 min
- 7
Eigenvalues and eigenvectors
~50 minVerify, find, move and judge the eigenvalues of a 2×2.
- DrillRead an eigenvalue off a vector14 min
- DrillFind both eigenvalues14 min
- DrillMove the eigenvalue11 min
- DrillWill it diagonalise11 min
- 8
Orthogonality and fitting
~59 minProject, classify, strip an overlap, and form the normal equations.
- DrillProject onto a line14 min
- DrillOrthogonal or orthonormal11 min
- DrillTake one Gram–Schmidt step14 min
- DrillForm the normal equations20 min
- 9
Spectral structure
~39 minClassify a form, size the singular values, and read the conditioning.
- DrillClassify a quadratic form14 min
- DrillFind the singular values14 min
- DrillRead the condition number11 min
More in Algorithms & interviews
Keep going
Discrete Mathematics Drills
MA101 taught it once. This is the volume.
Intermediate~8h8 modules
Interview: Two Pointers & Sliding Window
Read the problem. Then say whether a window applies at all.
Intermediate~3h4 modules
Interview: Trees & Graphs
One skeleton. Then the family it answers.
Intermediate~5h6 modules
Interview: Dynamic Programming
Most problems are not new. Learn to see the shape.
Advanced~5h5 modules
MA201 taught it once. This is the volume.
The first item is free. ~7h of focused work, at your own pace.
Advanced~7h9 modules