Write the equation useful to calculate half-life `(t_(1//2))` values for zero and first order reactions.

Explanation

Half life `(t_(1//2))` of zero order reaction
At half life `(t_(1//2))[R]=([R]_(0))/(2)`
`therefore t_(1//2)=([R_(0)])/(2k)`
Half life of a first order reaction
`t_(1//2) =(0.693)/(k)`
k = rate constant