When does cosecant=2?

1 Answer
Mar 19, 2018

x in {pi/6, (5pi)/6 } + 2pi nx{π6,5π6}+2πn where n in mathbb{Z}.

Explanation:

We want to solve when
csc(x) = 2

but cosecant is an ugly function. Let's make it into sines and cosines. That's not hard at all:
csc(x) = 1/sin(x)
so therefore we want to find when
sin(x) = 1/2

This happens in a 30-60-90 triangle! So we can write down a few times that this happens, based on our knowledge of the unit circle:
x = pi/6, (5pi)/6, (13pi)/6, (17pi)/6, ...
i.e.
x = {pi/6, (5pi)/6 } + 2pi n where n in mathbb{Z}.