solve using matlab

1- Matrix mat is a 2-layers matrix which its 1* layer and 2nd layer are defined as [1:3;0:2) and (-4:-2;1: 3) respectively, find sum(mat(:,2,1).* mat(:,2,2)). 2- Find the sum of the first 20 terms of the harmonic series where n is an integer variable greater than one. 1 1 1 1+ + + ... + 2 3 n 3- If cumsum operator of matrix mat is equal to 2 1 1 -1 2 0 find the product of elements related to the 2nd row of matrix mat. 4-If a = [2: 2:6;1: 3), b = (1-1; 2:3; 4 -5), and c = (34 20:17 - 10) what is the answer of isequal(c.a*b)? 5- Consider matrix a = (-11; 0 3), if we copy this matrix into two rows and three columns and name it b, find the summation of elements in matrix c which is defined in follows: c = b == repelem(a,2,3)