SEM 2 Flashcards
Can the hcf be negative
Yes
What is the prime number formula (Works up to n = 41)?
P(n) = n^2 - n + 41
What are the steps of mathematical induction?
Prove P(N) is true
Prove P(k+1) is true given P(k) is true
Strong induction?
Like mathematical except
P(k + 1) is true when P(N), P(N + 1) … is true
What is fermats little theorem?
a^p = a mod p
a^p-1 = 1 mod p (if p is not factor of a)
Key generation: n = ?
pq
Key Gen: e = ?
e is between 1 and (p-1)(q-1) and
e and (p-1)(q-1) are coprime
Key gen: d = ?
d > 0 such that
de == 1 mod (p-1)(q-1)
What is the public key?
(n,e)
What is private key?
d
How to encrypt?
For each value M
c = M^e mod n
How to decrypt?
M = c^d mod n
How to find inverse of 2x2 matrix?
1/ad - bc (d, -b, -c, a)
How to find inverse of any matrix (not 2x2)
- Write identity matrix next to it
- Turn left side into identity matrix and right side is inverse
What is minor?
Determinant (without working out result)
What is cofactor?
Multiply minor by -1