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(Solved): Find the smallest positive integer for which xmod3=2 and xmod4=3 What is the next smallest integer ...
Find the smallest positive integer for which xmod3=2 and xmod4=3 What is the next smallest integer with this property? [You will have to do some trial and error, but thinking about divisiblity should lead you to some patterns.]
The goal of this exercise is to practice finding the inverse modulo m of some (relatively prime) integer n. We will find the inverse of 5 modulo 17 , i.e., an integer c such that 5c?1(mod17). First we perform the Euclidean algorithm on 5 and 17 : 17?=3?+=2+1? [Note your answers on the second row should match the ones on the first row.] Thus gcd(5,17)=1, i.e., 5 and 17 are relatively prime. Now we run the Euclidean algorithm backwards to write 1=17s+5t for suitable integers s,t. s= when we look at the equation 17s+5t?1(mod17), the multiple of 17 becomes zero and so we get 5t=1(mod17). Hence the multiplicative inverse of 5 modulo 17 is