Trig Equations in the Calculator

[peep1963]

Hi. This is easy, I think. I need help in putting trig equations in the calculator. For example:

Solve the equation secX=4.2 for 0 to 2pi. (Radians)

I know I have to isolate my X. That would make the equation

X=sec^(-1)(4.2)

Using this I have to find my reference angle by putting it in the calculator. This is what I don't know how to do. I cant find the inverses of csc/sec/cot using the calculator. I tried 1/cos(4.2), then cos^(-1)(Ans) and vice versa. I know that the answer is like 1.3304. Either I'm pushin it in wrong or I don''t know what I'm doing. Usually, it's the latter.

Thanks

P.S.
I don't think this has anything to do with it but I use a TI-84.
and yes it was in radian mode

 

[Unco]

We have sec(x) = 4.2, not x = sec(4.2).

So use cos^-1(1/(4.2)), not 1/cos(4.2).