+ 2 = → = ( − ) = ( − ), 2 = ln = ln = ∙ = + 2 = = = ln . 2 + 2 + 2 2 ( − ) − 2 ln ( − ) − ln = + 2 = = ( − ) ( − ) 2 600 (600 − 300) − 300 ∙ ln = 300 = 0.3068 або ≈ 30.7 %. (600 − 300) 218