Ask your own question, for FREE!
Mathematics 13 Online
OpenStudy (anonymous):

calculate

OpenStudy (anonymous):

\[3^{64}\mod 67\]

OpenStudy (anonymous):

by repeated squaring or fermat theorem or otherwise

OpenStudy (amistre64):

3^4 = 81 = 14 mod 67

OpenStudy (amistre64):

(14*14) = 62 mod 67

OpenStudy (amistre64):

or -5 mod 67 might be simpler to work with

OpenStudy (anonymous):

can this simplify to a number

OpenStudy (amistre64):

it eventually goes to 15 i believe

OpenStudy (anonymous):

from 3^64 mod 67 3433683820292512484657849089281 mod 67 I got 15? Check with everyone else...

OpenStudy (anonymous):

ye,15 is correct

OpenStudy (anonymous):

Great! You got it then

OpenStudy (amistre64):

3^(64) mod 67 (3^4)^16 mod 67 (14)^16 mod 67 (14^2)^8 mod 67 (-5)^8 mod 67 (25)^4 mod 67 (22)^2 mod 67 15 mod 67

OpenStudy (anonymous):

15 mod 67 = 15

OpenStudy (anonymous):

can we use fermat little theorem \[a^{p-1}\equiv 1\mod p\]

OpenStudy (amistre64):

64 = 66-2 so maybe

OpenStudy (anonymous):

\[3^{66}\equiv 1\mod 67\] \[3^23^{64}\equiv 1\mod 67\]

OpenStudy (anonymous):

so we just need to invert 9 mod 67. You can either do this by the Euclidean algorithm, or by inspection. For example, 67 ยท 2 + 1 = 135 = 15*9

OpenStudy (anonymous):

wat is the \[9^{-1}\equiv 15\mod 67\]

Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!
Can't find your answer? Make a FREE account and ask your own questions, OR help others and earn volunteer hours!

Join our real-time social learning platform and learn together with your friends!