What is sin(-90 degrees)?

Consider that -90° corresponds to 270° (the minus sign is to turn clockwise instead of counter-clockwise): so: sin(-90°)=sin(270°)=-1

Malia tried to prove that cos pheta = sin 90 degrees - pheta using the following diagram. her proof is not

sin 90 Degrees Equals 1 Why?

How is sin (90°+θ) =cosθ? - Quora

Sin 90 Degrees - Find Value of Sin 90 Degrees

Using the unit circle to find sin(45 degrees)

Trigonometric Proof of sin(90°+θ) formula

OAT Physics Chapter 69: Magneticsm Flashcards

Sin 90 Degrees Value, Calculation, Periodicity & Examples

Solving Sin (90+Theta) = Cos - Explanation

Sin 90 Degrees: Formula, Examples, Questions

Number 90 - All about number ninety

If 0 degrees < theta < 90 degrees, is sin theta equal to cos (90 degrees theta), and for what reason?