I'm just starting so excuse my ignorance. anyway, I'm trying to write a simple math program which computes the value of a trigonometric function. Basically just input one value and get another out, but I have two problems:

1. even with cmath included, the constant pi is not provided(I tried PI)

2. I can't seem to input values in the form of division ie 1/2, pi/3. I declared the input variable type double so does that mean you can't enter fractions during cin?

btw, I'm using Dev C++ V4.9.9.2