Trig functions on iPhone calculator?

The "h" functions are hyperbolic functions (hyperbolic sine, consine and tangent); see http://en.wikipedia.org/wiki/Hyperbolic_function.

Secant, cosecant and cotangent can be calculated as the reciprocal of cosine, sine and tangent using teh 1/x function (see http://en.wikipedia.org/wiki/Trigonometric_functions#Reciprocal_functions).

The app store is full of alternative calulators as well, including reproductions of some of the Hewlett Packard ones such as the 15C.

You're welcome. I'm sure there are plenty of practice problems available on the internet. Try googling something like "trig function practice problems". Here's one at random: http://serc.carleton.edu/mathyouneed/trigonometry/BasicTrigSP.html.

Read http://en.wikipedia.org/wiki/Hyperbolic_function

You're welcome. Good luck!