Posted by Jillian on Friday, December 9, 2011 at 2:05pm.
State the exact values of the following.
cos(360 degrees)
sec(7pi/2)
tan(9pi/2)
How do I do these?
Thanks!

Math  Steve, Friday, December 9, 2011 at 3:04pm
Remember you can add or subtract 2pi = 360° without changing the values of the trig functions.
Then recall that for sin,tan,ctn,csc, f(x) = f(x)
for cos, sec, f(x) = f(x)
cos 360° = cos(360°360°) = cos 0°
sec(7pi/2) = sec(7pi/2  4pi) = sec(pi/2) = sec(pi/2)
tan(9pi/2) = tan(9pi/2 + 4pi) = tan(pi/2) = tan(pi/2)