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.

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

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.

You're welcome. Good luck!