Evaluate the integral: $$ I = \int \frac{2}{1 + x + x^2} \,dx. $$
\(\int\frac{2\cos 2x}{(1+\sin 2x)(1+\cos 2x)}dx=\)
Out of the first 5 consecutive natural numbers, if two different numbers x and y are chosen at random, then the probability that x4- y4 is divisible by 5 is: