int (pi^2/4 pi^2) sin x^(1/2)/x^(1/2) dx = | t = x^(1/2), x = t^2, dx = 2 * t dt | =
= int (pi/2 pi) sin t/t * 2 * t dt = 2 * int (pi/2 pi) sin t dt = 2 * (-cos t)_{pi/2}^{pi} =
= 2 * (-cos pi + cos pi/2) = 2