ba esteghra roye n be rahati hal mishe baraye n farz mikonim va baraye n+1 esbat mikonim dar hal jomle hayi ke be n+1 rabti nadar ro farze esteghra mizanim ama jomlehaye marbot ra beshekl zir baraye har i morabae kamel mikonim
a_n+1*b_i+b_n+1*a_i kolan be tavan 2