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

Missouri State University - Missouri State

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

Gravity as Geometry. The Four Fundamental Forces, Part 1…

trigonometry - Easy way of memorizing values of sine, cosine, and

How to understand trigonometry - Quora

Sin x = cos (90-x) but I can't solve this trig! Does anyone know how to solve this kind of problem?? : r/Sat