For any r, s ∈ N, show how to order the numbers 1, 2, . ....
For any r, s ∈ N, show how to order the numbers 1, 2, . . . , rs
so that the resulting sequence has no increasing subsequence of
length > r and no decreasing subsequence of length > s.
R= Ro(1/2)n n= number of half lifetimes= t/t1/2 (a)n= 2/2= 1 R=
Ro(1/2)n R=3000(1/2)1 R= 1500 counts/sec (b)n= 6/2= 3 R= Ro(1/2)n
R=3000(1/2)3 R= 375 counts/sec (c) n= 10/2= 5 R= Ro(1/2)n
R=3000(1/2)5 R= 93.75 counts/sec (d) n= 20/2= 10 R= Ro(1/2)n
R=3000(1/2)10 R= 2.93 counts/sec
What is the mean life of this nucleus?
f. Suppose that the Geiger counter detects 10% of all the
radioactive decays.
What is the total number of radioactive nuclei at time t =
0?...
(a) Show that the lines
r 1 (t) = (2,1,−4) + t(−1,1,−1) and r 2 (s) = (1,0,0) +
s(0,1,−2)
are skew.
(b) The two lines in (a) lie in parallel planes. Find equations for
these two planes. Express your
answer in the form ax+by+cz +d = 0. [Hint: The two planes will
share a normal vector n. How would one find n?]
would one find n?]
Show that {t_(1,s) : 2 ≤ s ≤ n} is a minimal generating set for
S_n. You may use the fact that {t_(r,s) : 1 ≤ r < s ≤ n}, as
defined in the outline, generates S_n.
let G = D2n =
{e,r,r^2,...,rn-1,s,sr,sr2,..,srn-1}
a diedergroup of order 2n, where n >=3
(a) prove that [G,G] = <r2>
(b) prove that G/[G,G] consists of two elements if n is uneven and
4 elements if n is even
1. Let α < β be real numbers and N ∈ N.
(a). Show that if β − α > N then there are at least N
distinct integers strictly between β and α.
(b). Show that if β > α are real numbers then there is a
rational number q ∈ Q such β > q > α.
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2. Let x, y, z be real numbers.The absolute value of x is
defined by
|x|= x, if x ≥...