how to type in arcsec?

Most calcs won't do that - you have to change like geno did first.

With the web2.calc you can do it straight out!  

What do you mean?

It is easy. First, type an "a" then an "r" then a "c" then an "s" then an "e" then a "c" and finally another "a"

If you want the trigonometric function equivalent, do the above on Google, just add “ant” to it. It is amazing what you can learn there. Though, in your case it is probably a waste of time and band width. 

To use your caclulator, you will need to change from sec to cos.

sec = 1/cos

So if you want the arecsec(3.456) first find 1/3.456 = 0.28935

Then find the arccos(0.28935).

Post back if you need more help.

Just hit the"2nd" button on the calculator....you will see the"asec" function button....