In a triangle \(ABC\), \(\displaystyle \frac{a(rr_1+r_2r_3)}{r_1-r+r_2r_3} =\;?\)
What is the angle between the hour and minute hands at 4:30?
The following graph indicates the system containing 1 mole of gas involving various steps. When it moves from Z to X, the type of undergoing process is: