79. find: dr -1+ xx (a) 0 (b) 1 (c) t (d) 27t 80. a sequence is a mapping whose domain is the set or. (a) real numbers (b) complex numbers (c) natural numbers (

79. Find: dr -1+ Xx (A) 0 (B) 1 (C) T (D) 27T 80. A sequence is a mapping whose domain is the set or. (A) real numbers (B) complex numbers (C) natural numbers (D) None of these 81. The sequence {s,}, where s, = e,n e N is a sequence. (A) decreasing (B) increasing (C) neither increasing nor decreasing (D) None of these 82. The sequence {s,}, where s, = n',n eN is a, sequence. (A) decreasing (B) increasing (C)neither increasing nor decreasing (D) None of these 83. Which of the following is an improper integral ? (B) (D) None of these 84. Iffand g be two positive functions such that ) S g(x), for all xr in la, b], then by comparison test dx converges if: (A) gd diverges (B)gd converges (D) None of these (C)gde is unbounded