- Problem 1 (3 marks). Use method COUNT1 to show that the following set is countable: {nnN0}{7nnN0,n3}. To get full marks, show clearly as a function of n the array index where each n and each 7n gets inserted. - Problem 2 (2 marks). Indicate whether each of the following identities is true or false-no explanations required. 1. (02)3=0(20)222 2. (0(12)210)3=0(1(21)20)310 3. 0((02)210)3=(002021)30 4. ((021)2001)4=00((102)201)301