In: Advanced Math
1: (an) and (bn) are bounded sequences:
(a) prove that limsup(-an) = -liminf(an)
(b) for any c>0, prove that
limsup(can) = climsup(an)
and
liminf(can) = climinf(an)
(c) prove that
limsup(an+bn) ≤ (limsup(an)) + (limsup(bn))
and
liminf(an+bn) ≥ (liminf(an)) + (liminf(bn))
(d) If an and bn are made of nonnegative terms, prove that
limsup(anbn) ≤ (limsup(an)) x (limsup(bn))
and
liminf(anbn) ≥ (liminnf(an)) x (liminf(bn))
(e) prove that
limsup(an+1) = limsup(an)
and
liminf(an+1) = liminf(an)