## A twin primes is a pair of prime numbers such that the difference between them is 2. For example, 5 and 7 are twin primes, and 17 and 19 is

Question

A twin primes is a pair of prime numbers such that the difference between them is 2. For example, 5 and 7 are twin primes, and 17 and 19 is another pair of twin primes. Write a program that finds all the twin primes between 10 and 500, save the results in a two-column matrix, and output result nicely formatted. You can use the built-in function, isprime().

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2 weeks 2021-09-28T17:24:19+00:00 1 Answer 0

1. Answer:         There is 22 possible combinations.

Step-by-step explanation:

%a is equal or greater then 11 and it is odd

count=0;

P=[];

for a=11:2:499

b=a+2;

%assume a and b are prime;

prime=1;

%check if a and b are prime

for k=2:ceil(sqrt(b))

%if a OR b is divisible by k, break

%it is not prime

if mod(a, k)==0 | mod(b, k)==0

prime=0;

break;

end

end

if prime

count=count+1;

P(count, :)=[a b];

end

end

fprintf(‘There is %d possible combinations.\n’, count)

display(P)

There is 22 possible combinations.

P =

11    13

17    19

29    31

41    43

59    61

71    73

101   103

107   109

137   139

149   151

179   181

191   193

197   199

227   229

239   241

269   271

281   283

311   313

347   349

419   421

431   433

461   463