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Find the remainder when 3*3^2*3^3*...*3^43 is divided by 11.

 Jul 7, 2021

Best Answer 

 #1
avatar+2407 
+2

If we add all the exponents up, we get 3^(1+2+3+4... 43) = 3^(946). 

 

3, 9, 27, 81, 243, 729...

3, 9, 5, 4, 1, 3....

There is a cycle of 3, 9, 5, 4, 1 in mod 11. 

946 = 1 mod 11, and the first number in the cycle of 3, 9, 5, 4, 1 is 3. 

 

=^._.^=

 Jul 7, 2021
 #1
avatar+2407 
+2
Best Answer

If we add all the exponents up, we get 3^(1+2+3+4... 43) = 3^(946). 

 

3, 9, 27, 81, 243, 729...

3, 9, 5, 4, 1, 3....

There is a cycle of 3, 9, 5, 4, 1 in mod 11. 

946 = 1 mod 11, and the first number in the cycle of 3, 9, 5, 4, 1 is 3. 

 

=^._.^=

catmg Jul 7, 2021
 #2
avatar+26396 
+2

Find the remainder when 33233343 is divided by 11.

 

33233343=31+2+3+42+43=3(1+43243)=3(44243)=32243=3946

 

Euler:3ϕ(11)1(mod11)|ϕ(11)=10, ϕ(p)=p1310=1(mod11)

 

3946(mod11)31094+6(mod11)(310)9436(mod11)|3101(mod11)19436(mod11)36(mod11)729(mod11)3946(mod11)3(mod11)

 

laugh

 Jul 8, 2021

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