5. Express the following sum using Sigma notation. 2-4+6-8 +10-12+ 14- 16+ .. 100 50 100 (a) Σ(-1)n-1.2n (b) Σ (-1)"-12n (c) Σ (n +1). (-1)"+1 (d) Σ-2n (e) None of thes né¯0 n-l n=0 n-1 6. In the following equation, A and B are fixed constants lim cane-=3 What must the ratio be equal to? A (a)=1 (e) (b) 1-3 (c) 6 (d) None of these -= B 2