Hi. I was able to find the solution, option D, by plugging the different angles. I'm not sure if this is the best way to solve the problem though. Any ideas?
First, do you know the basic definitions and trig identities? The very first thing I recommend is writing every thing in terms of sine and cosine, using the definitions of "tangent" and "secant". Then use a trig identity to write a quadratic equation in terms or "cosine" only and, finally, solve the equation.
I see Plato got in just ahead of me and suggested writing it as a quadratic equation in "secant" rather than "cosine"! Much of a muchness.
I tried the quadratic formula way for a different problem but I didn't get the right solution:
is there a difference between writing it as a quadratic formula in sine or any of the other basic trig definitions?