# Why inverse document frequency is needed in TF-IDF model?

## Why inverse document frequency is needed in TF-IDF model?

4 -Inverse Document Frequency(IDF): Thus we need to weigh down the frequent terms while scale up the rare ones, by computing IDF, an inverse document frequency factor is incorporated which diminishes the weight of terms that occur very frequently in the document set and increases the weight of terms that occur rarely.

**How do you find the frequency of an inverse document?**

The inverse document frequency is a measure of whether a term is common or rare in a given document corpus. It is obtained by dividing the total number of documents by the number of documents containing the term in the corpus.

### What is inverse frequency?

The period is the duration of time of one cycle in a repeating event, so the period is the reciprocal of the frequency.

**What is TF-IDF and also explain it with example?**

TF*IDF is used by search engines to better understand the content that is undervalued. For example, when you search for “Coke” on Google, Google may use TF*IDF to figure out if a page titled “COKE” is about: a) Coca-Cola. b) Cocaine.

#### What is meant by TF term frequency?

Term frequency (TF) means how often a term occurs in a document. In the context of natural language, terms correspond to words or phrases. But terms could also represent any token in text. To reduce this effect, term frequency is often divided by the total number of terms in the document as a way of normalization.

**Is wavelength the inverse of frequency?**

Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths. The range of wavelengths or frequencies for wave phenomena is called a spectrum.

## Why time period is inverse of frequency?

We know that frequency and time period are the inversely proportional quantities form the definition of the frequency and time period. The frequency and period are inverse functions because when the frequency is high, then the time period is low, or when the time period is low, then the frequency is increased.