What is the chromatic number of an $$n$$-vertex simple connected graph which does not contain any odd length cycle? Assume $$n \ge 2$$.

$$\int\limits_0^{\pi /4} {\left( {1 - \tan x} \right)/\left( {1 + \tan x} \right)dx} $$ $$\,\,\,\,\,\,$$ evaluates to

A CPU generally handles an interrupt by executing an interrupt service routine

In the following process state transition diagram for a uniprocessor system, assume that there are always some processes in the ready state:

Now consider the following statements:
$$1.\,\,\,$$ If a process makes a transition $$D,$$ it would result in another process making transition $$A$$ immediately.
$$2.\,\,\,$$ $$A$$ process $${P_2}$$ in blocked state can make transition $$E$$ while another process $${P_1}$$ is in running state.
$$3.\,\,\,$$ The $$OS$$ uses preemptive scheduling.
$$4.\,\,\,$$ The $$OS$$ uses non-preemptive scheduling. Which of the above statements are TRUE?