Find the number of matrixes a and b that on multiplication mod 2 gives c
Answers
Answer:
Modular multiplication. ... We will prove that (A * B) mod C = (A mod C * B mod C) mod C ... LHS = (C * C * Q1 * Q2 + C * Q1 * R2 + C * Q2 * R1 + R1 * R 2 ) mod C ..... You multiply 4 times 7 normally to get 28 and since one number is positive and one is negative the answer
Step-by-step explanation:
We will prove that (A * B) mod C = (A mod C * B mod C) mod C
We must show that LHS = RHS
From the quotient remainder theorem we can write A and B as:
A = C * Q1 + R1 where 0 ≤ R1 < C and Q1 is some integer. A mod C = R1
B = C * Q2 + R2 where 0 ≤ R2 < C and Q2 is some integer. B mod C = R2
LHS = (A * B) mod C
LHS = ((C * Q1 + R1 ) * (C * Q2 + R2) ) mod C
LHS = (C * C * Q1 * Q2 + C * Q1 * R2 + C * Q2 * R1 + R1 * R 2 ) mod C
LHS = (C * (C * Q1 * Q2 + Q1 * R2 + Q2 * R1) + R1 * R 2 ) mod C
We can eliminate the multiples of C when we take the mod C
LHS = (R1 * R2) mod C
Next let's do the RHS
RHS = (A mod C * B mod C) mod C
RHS = (R1 * R2 ) mod C
Therefore RHS = LHS
LHS = RHS = (R1 * R2 ) mod C
How to calculate the modulo - an example
- Start by choosing the initial number (before performing the modulo operation). ...
- Choose the divisor. ...
- Divide one number by the other, rounding down: 250 / 24 = 10 . ...
- Multiply the divisor by the quotient. ...
- Subtract this number from your initial number (dividend