In a game, two players $$X$$ and $$Y$$ toss a coin alternately. Whoever gets a 'head' first, wins the game and the game is terminated. Assuming that players $$X$$ starts the game the probability of player $$X$$ winning the game is

For a random variable $$\,x\left( { - \infty < x < \infty } \right)\,\,$$ following normal distribution, the mean is $$\,\mu = 100\,\,.$$ If the probability is $$\,\,P = \alpha \,\,$$ for $$\,\,x \ge 110.\,\,\,$$ Then the probability of $$x$$ lying $$b/w$$ $$90$$ and $$110$$ i.e., $$\,P\left( {90 \le x \le 110} \right)\,\,$$ and equal to

The solutions of the differential equation $${{{d^2}y} \over {d{x^2}}} + 2{{dy} \over {dx}} + 2y = 0\,\,$$ are

The value of the expression $${{ - 5 + 10i} \over {3 + 4i}}$$ is