Math CentralQuandaries & Queries


Question from Tom, a student:

I am having trouble with this question. For y > 1, the value of cosec [arccos (1/y)] is?

So far i have let arccos (1/y) = theta so , cos theta = 1/y

The answer is y/ sqroot (y*2 - 1), what are the steps in getting this answer, and is there a general rule for working these out? Thankyou.

Hi Tom,

I would draw a diagram. If arccos (1/y) = theta then


Use Pythagoras theorem to find the length of the third side of the triangle. From the diagram what is cosec(θ)?


About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS