Question

A very simple question for trigonometry! So lets say I want to use a formula for example csc = 1/sin a. Would that still apply if instead of sin a it is - sin a? If not, can I still use this formula is sin a is negative? Thanks!

Answer 1

Explanation:

csc = 1/sin a would be OK if you'd insert the argument 'a:'

csc a = 1/sin a is an identity (a relationship that is always true).

If you write csc a = 1 / (-sin a) you are creating a conditional equation which may be true for some values of a but not for all.