Looker Studio Function: ACOS

Category: Arithmetic function

The ACOS (arc cosine) function in Looker Studio is a mathematical tool that returns the arccosine, or inverse cosine, of a number. It’s primarily used to analyze relationships in datasets where cosine similarity or distribution patterns play a role, offering values in radians between 0 and π.

Purpose of the ACOS Function

1. Data Distribution Analysis :

The ACOS function helps identify how values are distributed within a dataset, particularly useful in scenarios involving vector directions or similarity metrics. It allows users to interpret angles and trends in data correlation visually.

2. Customer Segmentation : By applying the ACOS function on normalized data, businesses can classify customers into behavioral groups based on cosine similarity, identifying patterns among high-value customers versus low-engagement ones.

3. Decision Making :

ACOS supports strategic decision-making by quantifying patterns in datasets. Whether analyzing user engagement or product interest, it provides a numerical foundation to justify marketing or operational choices.

Type of Calculation:

Performance Benchmark

ACOS helps measure similarity in performance metrics, ideal for comparing sales reps, store locations, or campaign effectiveness when plotted in vector space.

Customer Segmentation

Cluster customers by analyzing cosine distance between purchasing behaviors. ACOS helps build more accurate persona models for targeted campaigns.

Time Series Analysis

Evaluate how patterns shift over time by converting time-series data into vectors and applying ACOS to understand trend alignment or divergence.


ACOS(value)

ParameterTypeDescription
ValuenumberA numeric input between -1 and 1

How Does the ACOS Function Work?

The ACOS function works by calculating the angle (in radians) whose cosine equals the given number. It is essential in geometric computations and is typically applied in fields involving directional data, vector similarities, or normalized correlation matrices.


When Should You Use ACOS?

    • Use the ACOS function when:

      • Analyzing cosine similarities between two data vectors.

      • Clustering or classifying customers based on behavior patterns.

      • Comparing performance or behavior alignment.

      • Converting a similarity score into a usable metric for visualization.

Example of ACOS with Result

Example 1: Basic Usage

ACOS(0.7071) ➝ 0.7853 (approx. 45 degrees)

Example 2: Column Usage 

ACOS(Sales_Similarity_Score)

Example 3: Handling Decimals and Scientific Notation

ACOS(1.0E-1) ➝ ACOS(0.1) ➝ 1.4706 radians

Example 4: Combining with Other Functions

DEGREES(ACOS(cosine_similarity)) ➝ Converts result from radians to degrees

Tips and Tricks

      • Normalize data before applying ACOS for accurate results.

      • Combine ACOS with DEGREES() for easier human interpretation.

      • Use error handling to catch out-of-bound inputs.

      • Apply ACOS to cosine similarity outputs for machine learning insights.

      • Great for vector-based recommendation engines.

1.What does the ACOS function return?

It returns the arccosine (inverse cosine) of a value in radians.

2.Can I input any number into ACOS?

No, input must be between -1 and 1. Any value outside this range will result in an error.

3. Is ACOS only for scientific data?

Not at all. It’s useful in marketing, finance, retail, and any field that analyzes vector-based similarities.

4. How do I convert ACOS output to degrees?

Wrap the function with DEGREES(), like: DEGREES(ACOS(0.5)).

5. Can I use ACOS for customer clustering?

Yes! Combine cosine similarity scores with ACOS to separate customer groups based on behavioral closeness.