So the reciprocal of the sine function is called the cosecant and is equal to the hypotenuse / opposite. The reciprocal of the cosine function is called the secant and is equal to the hypotenuse / adjacent, and the reciprocal of the tangent function is called the cotangent and is equal to the adjacent / opposite.

It is important to note that there is a big difference between the reciprocal value csc θ and sin^-1x. The cosecant function means 1/sin θ, while the second involves finding an angle whose sine is x.