A continuous random variable XXX has the CDF F(x)=1−e−x2F(x) = 1 - e^{-x^2}F(x)=1−e−x2 for x≥0x \ge 0x≥0. Find the expected value E[X]E[X]E[X].
π/2\sqrt{\pi}/2π/2
π/2\pi/2π/2
111
π\sqrt{\pi}π