Why is [math]\sin (-90^\circ)=-1[/math]? - Quora

Sin 90 degrees equal to 1 but why?

OpenBOM Basics – How to Create a Multi-Level (Hierarchical) BOM

Gauss Elimination Method Meaning and Solved Example

Origin: Data Analysis and Graphing Software

is it correct to say that sin theta =cos 90-theta why?​

Schaum's Outline of Matrix Operations (Schaum's Outlines): Bronson

How to evaluate arcsin(1) - Mathematics Skills - Learn/Expertise - Quora

Example 2 - In figure, ray OS stands on line POQ - Class 9

How to find the value of sine when the value of cosine is known - Quora

How did they calculate sin cos tan before calculators? - Quora

View question - Why is the sine of 90 degrees equal to 1?