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Implement sin(x) with precision constraints

Last updated: Mar 29, 2026

Quick Overview

This question evaluates understanding of numerical methods, floating-point arithmetic, and algorithmic implementation in the Coding & Algorithms domain by requiring an approximation of the sine function under explicit error bounds.

  • medium
  • Snapchat
  • Coding & Algorithms
  • Software Engineer

Implement sin(x) with precision constraints

Company: Snapchat

Role: Software Engineer

Category: Coding & Algorithms

Difficulty: medium

Interview Round: Technical Screen

## Coding Question: Implement `sin(x)` Implement a function that returns an approximation of the trigonometric sine function. ### Function signature - Input: a real number `x` (in radians) - Output: `sin(x)` as a floating-point number ### Restrictions - Do **not** call library trig functions (e.g., `sin`, `cos`, `tan`). - You may use basic arithmetic operations and constants. ### Accuracy requirement - Your result must satisfy: \(|\text{ans} - \sin(x)| \le \varepsilon\) - Assume the interviewer provides a specific `ε` (e.g., `1e-6`). ### Follow-ups 1. After writing a straightforward version, describe how you would **optimize** it (time and/or numerical stability). 2. In real systems, how would you further **engineer** this function for performance and reliability (e.g., handling large `|x|`, speed, testing, edge cases)? ### Notes - You may assume IEEE-754 `double` behavior. - Consider how your implementation behaves for very large magnitude `x` and near special points (e.g., around `0`, `π`, `π/2`).

Quick Answer: This question evaluates understanding of numerical methods, floating-point arithmetic, and algorithmic implementation in the Coding & Algorithms domain by requiring an approximation of the sine function under explicit error bounds.

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Snapchat
Nov 26, 2025, 12:00 AM
Software Engineer
Technical Screen
Coding & Algorithms
2
0

Coding Question: Implement sin(x)

Implement a function that returns an approximation of the trigonometric sine function.

Function signature

  • Input: a real number x (in radians)
  • Output: sin(x) as a floating-point number

Restrictions

  • Do not call library trig functions (e.g., sin , cos , tan ).
  • You may use basic arithmetic operations and constants.

Accuracy requirement

  • Your result must satisfy: ∣ans−sin⁡(x)∣≤ε|\text{ans} - \sin(x)| \le \varepsilon∣ans−sin(x)∣≤ε
  • Assume the interviewer provides a specific ε (e.g., 1e-6 ).

Follow-ups

  1. After writing a straightforward version, describe how you would optimize it (time and/or numerical stability).
  2. In real systems, how would you further engineer this function for performance and reliability (e.g., handling large |x| , speed, testing, edge cases)?

Notes

  • You may assume IEEE-754 double behavior.
  • Consider how your implementation behaves for very large magnitude x and near special points (e.g., around 0 , π , π/2 ).

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