Statement P is \(a + b = 4\).
Statement Q is \(\quad a = 1\) and \(b = 3\).
Which one of the following is correct?
$$\mathrm { P } \Rightarrow \mathrm { Q } , \quad \mathrm { P } \Leftrightarrow \mathrm { Q } , \quad \mathrm { P } \Leftarrow \mathrm { Q }$$
Statement R is \(\quad x = 2\).
Statement S is \(\quad x ^ { 2 } = 4\).
Which one of the following is correct?
$$R \Rightarrow S , \quad R \Leftrightarrow S , \quad R \Leftarrow S$$