_index.org

oral lexical retrieval

Last edited: August 8, 2025

oral lexical retrival is a class of discourse tasks which asks the subject to convert some semantic understanding (“concept”) into lexical expressions (“words”)

“ask a patient to describe a thing.”

Examples of oral lexical retrieval:

Source: CambridgeCore

Ordinary Differential Equation

Last edited: August 8, 2025

ODEs are Differential Equations in one independent variable: \(y(x)\).

Main Content:

Overarching Categories

order of equations

the order of an equation is the highest derivative of an equation

linear vs. non-linear differential equations

A solution of a differential equation is linear when solutions are closed under linear operations.

We can spot an ODE by seeing that each of its derivatives are seperated or in separable terms, and only to the first power—because that ends up being a linear equation (i.e. any two solutions satisfying the equation can add and scale to another solution).

Origins of American Conservatism

Last edited: August 8, 2025

Reading notes

conservatives in America make less sense because America is supposed to be liberal/new

For most Europeans who came to America, the whole purpose of their difficult and dis- ruptive journey to the New World was not to conserve European institutions but to leave them behind and to create something new, often an entirely new life

Three splits of conservatism in America

  1. those who are most concerned about economic or fiscal issues, that is, pro-business or “free-enterprise” conservatives
  2. those most concerned with religious or social issues, that is, pro-church or “traditional-values” conservatives
  3. those most concerned with national-security or defense issues, that is, pro-military or “patriotic” conservatives

Ronald Reagan unified the three conservatism

It was the achievement of Ronald Reagan that he was able in the late 1970s to unite these three different kinds of conservatism into one grand coalition.

orthogonal

Last edited: August 8, 2025

Two vectors are considered orthogonal if \(\langle u,v \rangle = 0\), that is, their inner product is \(0\).

See also orthogonality test.

orthogonality and \(0\)

  • \(0\) is orthogonal to every vector in \(v\) because \(\langle 0,v \rangle=0\) for every \(v\) because of the properties of inner product
  • \(0\) is the only vector orthogonal to itself as, by inner product definiteness, \(\langle v,v \rangle=0\) implies \(v=0\).

orthonormal

Last edited: August 8, 2025

A list of vectors is orthonormal if each vector is orthogonal to every other vector, and they all have norm 1.

In other words:

\begin{equation} \langle e_{j}, e_{k} \rangle = \begin{cases} 1, j = k\\ 0, j \neq k \end{cases} \end{equation}

The vectors should inner-product with itself to \(1\), and be orthogonal to all others.

Additional Information

orthonormal basis

See also orthonormal basis

Norm of an Orthogonal Linear Combination

\begin{equation} \| a_1e_1 + \dots + a_{m}e_{m} \|^{2} = |a_1|^{2} + \dots + |a_{m}|^{2} \end{equation}