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Module 2 · Maths for Data Module contents
Module 2  ·  Card 8 / 13intermediate

Matrix Transpose

Transposing a matrix flips its structure over its main diagonal, swapping its horizontal rows with its vertical columns.

The transpose of an m-by-n matrix produces a new matrix with dimensions n-by-m.

The entry originally located at row i and column j moves to row j and column i in the transposed matrix.

It is denoted by adding a capital T as a superscript, such as A transposed.

In data science, transposing aligns matrices for multiplication, switches perspectives between features and samples, and helps compute correlations.

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Module 02 · Maths for Data · 13 concepts
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Matrix Transpose, in more detail

The transpose is one of the simplest yet most fundamental operations in matrix algebra.

It reflects matrix entries across the main diagonal running from the top left to the bottom right.

The first row of the original matrix becomes the first column of the transposed matrix.

The second row becomes the second column, continuing across all available rows.

If the original matrix A has dimensions m by n, its transpose has dimensions n by m.

Transposing a column vector turns it into a row vector, and transposing a row vector creates a column vector.

If you transpose a matrix twice, you return to the exact original matrix: the transpose of A transposed is A.

When a square matrix equals its own transpose, it is symmetric across its main diagonal.

Covariance and correlation matrices are always symmetric because the covariance of x and y equals that of y and x.

An important algebraic rule governs transposed products: the transpose of A times B equals B transposed times A transposed.

Notice that the order of multiplication reverses when taking the transpose of a matrix product.

In data pipelines, transposing is necessary when matching dimensions between weight vectors and feature matrices.

Beginners often assume transposing rotates a matrix by ninety degrees, which is a geometric misconception.

Transposition reflects values diagonally, keeping the top left element fixed in place.

Transposing provides the structural flexibility needed to formulate regression equations and covariance calculations cleanly.

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One question on this card. Every option explains itself once you pick, right or wrong.

Question 1
A design matrix X has 50 rows representing customers and 6 columns representing features. What are the dimensions of X transposed?
Maths for Data

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