Introducing Secant, Co-Secant & Co-Tangent

ChoShaCao is one way to go, but let's face it, nobody except for one Brentwood student I know has ever done it. Instead, we'll always use the reciprocals method to find these puppies, since that will work in special and non-special triangles. We'll also get tons of practice rationalizing denominators, since that's usually the hardest thing about finding sec, csc & cot.