@@ -81,8 +84,117 @@ Math Calendar 2024 December
Dec 01
+
+Find \(-ijk\) where \(i,j,k\) are quaternions.
+
+
+
+Quaternions are an extension of complex numbers which is not commutative, but it
+is associative. Multiplication is defined where \(1\) is the identity element
+and the imaginary basis products are
+\[i^2=j^2=k^2=-1,\ ij=-ji=k,\ jk=-kj=i,\ ki=-ik=j\]
+So by using this
+\[-ijk=-(ij)k=-(k)k=-k^2=-(-1)=1\]
+
+
Dec 02
+
+Find the remainder whehn \(x^6+1\) is divided by \(x^2-x+1\).
+
+
+
+The most clear way to solve this would be to use polynomial division.
+
+
+
+
+ |
+ \(x^4\) |
+ \(+x^3\) |
+ \(+0x^2\) |
+ \(-x\) |
+ \(-1\) |
+
+
+ \(x^2\) |
+ \(-x\) |
+ \(+1\) |
+ \(x^6\) |
+ \(+0x^5\) |
+ \(+0x^4\) |
+ \(+0x^3\) |
+ \(+0x^2\) |
+ \(+0x\) |
+ \(+1\) |
+
+
+ |
+ \(-\) |
+ \((x^6\) |
+ \(-x^5\) |
+ \(+x^4)\) |
+ |
+
+
+ |
+ \(x^5\) |
+ \(-x^4\) |
+ \(+0x^3\) |
+ |
+
+
+ |
+ \(-\) |
+ \((x^5\) |
+ \(-x^4\) |
+ \(+x^3)\) |
+ |
+
+
+ |
+ \(-x^3\) |
+ \(+0x^2\) |
+ \(+0x\) |
+ |
+
+
+ |
+ \(-\) |
+ \((-x^3\) |
+ \(+x^2\) |
+ \(-x)\) |
+ |
+
+
+ |
+ \(-x^2\) |
+ \(+x\) |
+ \(+1\) |
+
+
+ |
+ \(-\) |
+ \((-x^2\) |
+ \(+x\) |
+ \(-1)\) |
+
+
+ |
+ \(2\) |
+
+
+
+
+This shows that the remainder is \(2\) and
+\[{x^6+1\over x^2-x+1}=x^4+x^3-x-1+{2\over x^2-x+1}\]
+One other possible way to see it for this problem is noticing that \(x^2-x+1\)
+is a factor of \(x^3+1\). Then \((x^3+1)(x^3-1)=x^6-1\) and adding the remainder
+of \(2\) shows that \(x^6+1=(x^6-1)+2\) where \(x^2-x+1\) is a factor of
+\(x^6-1\). Or it can also be found by seeing how to factor
+\[x^6-1=(x^3+1)(x^3-1)=(x+1)(x^2-x+1)(x-1)(x^2+x+1)\]
+
+
Dec 03
Dec 04
diff --git a/academic/misc/20240302-power-sum.html b/academic/misc/20240302-power-sum.html
index e31d3b5..f1c868e 100644
--- a/academic/misc/20240302-power-sum.html
+++ b/academic/misc/20240302-power-sum.html
@@ -53,7 +53,7 @@ Double Summation Method
of \(p-1\) powers. To see how we can do this, consider a table like below.
-
+
\(1^{p-1}\) | | | | |
\(2^{p-1}\) | \(2^{p-1}\) | | | |
\(3^{p-1}\) | \(3^{p-1}\) | \(3^{p-1}\) | | |
@@ -243,7 +243,7 @@ Matrix Methods
corresponds to a row and each \(j\) corresponds to a column.
-
+
\(c_1{1\choose0}\) | \(c_1{1\choose1}n\) |
| | | |
\(c_2{2\choose0}\) | \(c_2{2\choose1}n\) |
diff --git a/academic/misc/20240323-some-putnam-problems.html b/academic/misc/20240323-some-putnam-problems.html
index e273e7e..4476dda 100644
--- a/academic/misc/20240323-some-putnam-problems.html
+++ b/academic/misc/20240323-some-putnam-problems.html
@@ -38,7 +38,7 @@ Area in 2D Plane
following inequalities:
-
+
Quadrant | Inequality |
I: \(x\geq0,y\geq0\) | \(y\geq x-1\) |
II: \(x<0,y\geq0\) | \(y\geq-x-1\) |
diff --git a/academic/proj_euler/part0001.html b/academic/proj_euler/part0001.html
index 0874e5a..0c0b3a5 100644
--- a/academic/proj_euler/part0001.html
+++ b/academic/proj_euler/part0001.html
@@ -71,7 +71,7 @@ Problem 1
1000 so we should not count 1000.
-Answer:
233168
+Answer:
233168
Problem 2
@@ -138,7 +138,7 @@ Problem 2
Note: the largest term included in the sum is \(F_{33}=3524578\).
-Answer:
4613732
+Answer:
4613732
Problem 3
@@ -179,7 +179,7 @@ Problem 3
numbers.
-Answer:
6857
+Answer:
6857
The factorization is \(71\cdot839\cdot1471\cdot6857\)
Problem 4
@@ -236,7 +236,7 @@ Problem 4
print(largest)
-Answer:
906609
+Answer:
906609
The product is \(993\cdot913\)
Problem 5
@@ -316,7 +316,7 @@ Problem 5
print(result)
-Answer:
232792560
+Answer:
232792560
The factorization is:
\(2^4\cdot3^2\cdot5\cdot7\cdot11\cdot13\cdot17\cdot19\)
@@ -363,7 +363,7 @@ Problem 6
expected, the solution expression is also asymptotic to \(N^4/4\).
-Answer:
25164150
+Answer:
25164150
Problem 7
@@ -516,7 +516,7 @@ Problem 7
Note: the sieve size calculated to use is 116684, about 11% overestimated.
-Answer:
104743
+Answer:
104743
Problem 8
@@ -646,7 +646,7 @@ Problem 8
print(largest)
-Answer:
23514624000
+Answer:
23514624000
The consecutive digits forming this product are: 5576689664895
(starts with the last 3 digits on the 4th line)
@@ -735,7 +735,7 @@ Problem 9
print(a*b*c * d**3)
-Answer:
31875000
+Answer:
31875000
The triple is (200,375,425), 25 times the primitive triple (8,15,17)
Problem 10
@@ -788,7 +788,7 @@ Problem 10
Note: a total of 148933 primes are summed.
-Answer:
142913828922
+Answer:
142913828922
diff --git a/academic/proj_euler/part0011.html b/academic/proj_euler/part0011.html
index 8f848a5..187c39f 100644
--- a/academic/proj_euler/part0011.html
+++ b/academic/proj_euler/part0011.html
@@ -136,7 +136,7 @@ Problem 11
print(f'start at {sol_rc} going {sol_dir} multiply {sol_nums}')
-Answer:
70600674
+Answer:
70600674
Product is \(87\cdot97\cdot94\cdot89\) (starting in the 16th row and 4th column,
going along the up-right diagonal)
@@ -216,7 +216,7 @@ Problem 12
n += 1
-Answer:
76576500
+Answer:
76576500
The factorization is \(2^2\cdot3^2\cdot5^3\cdot7\cdot11\cdot13\cdot17\) and
it has \(3\cdot3\cdot4\cdot2\cdot2\cdot2\cdot2=576\) divisors
@@ -570,7 +570,7 @@ Problem 13
print(''.join(map(str,total[:10])))
-Answer:
5537376230
+Answer:
5537376230
Problem 14
@@ -637,7 +637,7 @@ Problem 14
integers.
-Answer:
837799
+Answer:
837799
Problem 15
@@ -714,7 +714,7 @@ Problem 15
Note: the solution does not fit in a 32 bit integer.
-Answer:
137846528820
+Answer:
137846528820
Problem 16
@@ -750,7 +750,7 @@ Problem 16
print(sum(number))
-Answer:
1366
+Answer:
1366
Problem 17
@@ -814,7 +814,7 @@ Problem 17
-
+
number | word form | length |
1 | one | 3 |
2 | two | 3 |
@@ -827,7 +827,7 @@ Problem 17
9 | nine | 4 |
| total | 36 |
-
+
number | word form | length |
10 | ten | 3 |
11 | eleven | 6 |
@@ -848,7 +848,7 @@ Problem 17
word like "twenty" which is used 10 times and each number 1-9.
-
+
tens word | length | letters used |
twenty | 6 | 10×6 + 36 = 96 |
thirty | 6 | 10×6 + 36 = 96 |
@@ -873,7 +873,7 @@ Problem 17
adding all these together, we get the answer.
-Answer:
21124
+Answer:
21124
Problem 18
@@ -950,7 +950,7 @@ Problem 18
print(largestsum)
-Answer:
1074
The path is:
+Answer:
1074
The path is:
75, 64, 82, 87, 82, 75, 73, 28, 83, 32, 91, 78, 58, 73, 93
Problem 19
@@ -991,7 +991,7 @@ Problem 19
print(count)
-Answer:
171
+Answer:
171
Problem 20
@@ -1032,7 +1032,7 @@ Problem 20
print(sum(num))
-Answer:
648
+Answer:
648
diff --git a/academic/proj_euler/part0021.html b/academic/proj_euler/part0021.html
index a4a6491..0a1534b 100644
--- a/academic/proj_euler/part0021.html
+++ b/academic/proj_euler/part0021.html
@@ -111,7 +111,7 @@ Problem 21
print(total)
-Answer:
31626
+Answer:
31626
The amicable pairs are (220,284), (1184,1210), (2620,2924), (5020,5564),
(6232,6368)
@@ -148,7 +148,7 @@ Problem 22
print(sum((i+1)*name_value(name) for i,name in enumerate(data)))
-Answer:
871198282
+Answer:
871198282
Problem 23
@@ -221,7 +221,7 @@ Problem 23
Wikipedia.
-Answer:
4179871
+Answer:
4179871
Problem 24
@@ -344,7 +344,7 @@ Problem 24
\(2\times9!+7\times8!\). Below is a table showing the work:
-
+
step |
digit chosen |
@@ -424,7 +424,7 @@ Problem 24
remaining digits) factorial to take.
-Answer:
2783915460
+Answer:
2783915460
Problem 25
@@ -507,7 +507,7 @@ Problem 25
number of digits in these numbers.
-Answer:
4782
+Answer:
4782
Problem 26
@@ -571,7 +571,7 @@ Problem 26
print(num)
-Answer:
983
+Answer:
983
The cycle length is 982
Problem 27
@@ -657,7 +657,7 @@ Problem 27
print(amax*bmax)
-Answer:
-59231
+Answer:
-59231
The function is \(f(n)=n^2-61x+971\)
Problem 28
@@ -715,7 +715,7 @@ Problem 28
=1+\frac{S}{3}(16S^2+30S+26)
\end{align}\]
-Answer:
669171001
+Answer:
669171001
Problem 29
@@ -771,7 +771,7 @@ Problem 29
counting it for the representation with the smallest base.
-Answer:
9183
+Answer:
9183
Problem 30
@@ -801,7 +801,7 @@ Problem 30
print(total)
-Answer:
443839
+Answer:
443839
The numbers are 4150, 4151, 54748, 92727, 93084, 194979
diff --git a/academic/proj_euler/part0031.html b/academic/proj_euler/part0031.html
index ff12e56..010de22 100644
--- a/academic/proj_euler/part0031.html
+++ b/academic/proj_euler/part0031.html
@@ -107,7 +107,7 @@ Problem 31
print(W[P])
-Answer:
73682
+Answer:
73682
Problem 32
@@ -141,7 +141,7 @@ Problem 32
print(sum(c_set))
-Answer:
45228
+Answer:
45228
The product identities are:
4 * 1738 = 6952
@@ -201,7 +201,7 @@ Problem 33
print(product.denominator)
-Answer:
100
+Answer:
100
The 4 fractions are: 16/64, 19/95, 26/65, 49/98 which simplify to
1/4, 1/5, 2/5, 1/2 and multiply to 1/100
@@ -241,7 +241,7 @@ Problem 34
print(total)
-Answer:
40730
+Answer:
40730
There are only 2 such numbers: 145, 40585
Problem 35
@@ -318,7 +318,7 @@ Problem 35
print(len(circulars))
-Answer:
55
+Answer:
55
Full list: 2, 3, 5, 7, 11, 13, 17, 31, 37, 71, 73, 79, 97, 113, 131, 197, 199,
311, 337, 373, 719, 733, 919, 971, 991, 1193, 1931, 3119, 3779, 7793, 7937,
9311, 9377, 11939, 19391, 19937, 37199, 39119, 71993,
@@ -385,7 +385,7 @@ Problem 36
print(total)
-Answer:
872187
+Answer:
872187
The double palindromes: 1, 3, 5, 7, 9, 33, 99, 313, 585, 717, 7447, 9009,
15351, 32223, 39993, 53235, 53835, 73737, 585585
@@ -458,7 +458,7 @@ Problem 37
print(sum(lrtrunc))
-Answer:
748317
+Answer:
748317
Prime list: 23, 37, 53, 73, 313, 317, 373, 797, 3137, 3797, 739397
Problem 38
@@ -490,7 +490,7 @@ Problem 38
print(largest)
-Answer:
932718654
+Answer:
932718654
All starting numbers: 1, 9, 192, 219, 273, 327, 6729, 6792, 6927,
7269, 7293, 7329, 7692, 7923, 7932, 9267, 9273, 9327
@@ -548,7 +548,7 @@ Problem 39
print(maxp[0])
-Answer:
840
+Answer:
840
There are 8 solutions for perimeter 840
Problem 40
@@ -568,7 +568,7 @@ Problem 40
showing the work:
-
+
number range |
total digits |
@@ -661,7 +661,7 @@ Problem 40
print(prod)
-Answer:
210
+Answer:
210
The 7 digits multiplied are: 1, 1, 5, 3, 7, 2, 1
diff --git a/academic/proj_euler/part0041.html b/academic/proj_euler/part0041.html
index 8967148..5d00c1e 100644
--- a/academic/proj_euler/part0041.html
+++ b/academic/proj_euler/part0041.html
@@ -84,7 +84,7 @@ Problem 41
primes.
-Answer:
7652413
+Answer:
7652413
Problem 42
@@ -128,7 +128,7 @@ Problem 42
print(sum(1 for x in data if triangle(x)))
-Answer:
162
+Answer:
162
Problem 43
@@ -183,7 +183,7 @@ Problem 43
print(sum(numbers))
-Answer:
16695334890
+Answer:
16695334890
There are 6 such numbers:
1460357289, 1430952867, 1406357289, 4160357289, 4130952867, 4106357289
@@ -385,7 +385,7 @@ Problem 44
i += 1
-Answer:
5482660
+Answer:
5482660
\(P_{1912}=P_{2167}-P_{1020}\) and \(P_{2395}=P_{2167}+P_{1020}\)
The next 3 solutions (k,j,i) are (121168,111972,46303),
(110461,95506,55500), (91650,52430,75172)
@@ -549,7 +549,7 @@ Problem 45
\(T_{2084377905}=P_{1203416145}=H_{1042188953}=2172315626468283465\)
-Answer:
1533776805
+Answer:
1533776805
\(T_{55385}=P_{31977}=H_{27693}\)
Problem 46
@@ -590,7 +590,7 @@ Problem 46
n += 2
-Answer:
5777
+Answer:
5777
There is only 1 other known counterexample: 5993
Problem 47
@@ -653,7 +653,7 @@ Problem 47
sieve_size *= 2 # double sieve size to try again
-Answer:
134043
+Answer:
134043
\(134043=3\cdot7\cdot13\cdot491\)
\(134044=2^2\cdot23\cdot31\cdot47\)
\(134045=5\cdot17\cdot19\cdot83\)
@@ -711,7 +711,7 @@ Problem 48
print(sum(modexp(x,x,10**10) for x in range(1,1+1000)) % 10**10)
-Answer:
9110846700
+Answer:
9110846700
Problem 49
@@ -776,7 +776,7 @@ Problem 49
print(''.join(map(str,sol)))
-Answer:
296962999629
+Answer:
296962999629
(2969, 6299, 9629), step size is also 3330
Problem 50
@@ -831,7 +831,7 @@ Problem 50
print(lsum)
-Answer:
997651
+Answer:
997651
diff --git a/mathstyles.css b/mathstyles.css
index 11ed7fb..703088d 100644
--- a/mathstyles.css
+++ b/mathstyles.css
@@ -19,21 +19,23 @@ body {
box-sizing: border-box;
}
-table {
+.table_normal {
border-collapse: collapse;
margin: 0 auto;
}
-th {
+.table_normal th {
background: lightgray;
+ border: 1px solid black;
+ padding: 2px;
}
-th, td {
+.table_normal td {
border: 1px solid black;
padding: 2px;
}
-details {
+.pe_answer {
background: lightgray;
}