#Inverse of an equation with matrices

14 messages · Page 1 of 1 (latest)

jagged marlin
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We have been given this equation which is an encryption function and we are told to find the decryption function which I assume would be the inverse of that function

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storm waspBOT
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jagged marlin
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so I rearranged the equation to get this but it doesnt spit out the right numbers

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have I done something wrong? is this possible?

lavish vale
jagged marlin
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heres my working for the question

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and when I use that equation to decrypt "yg" I get a matrix of 3 and 23/3 which cant be mapped back to a letter. I checked everything with calculators @lavish vale

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I used a 7 instead of a 6 in the calculations but even that gives me fractional answers

lavish vale
lavish vale
# jagged marlin

Ohh. I see. It's in ℤ12.
Sorry, I don't know how to work with that.

jagged marlin
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in case you were interested, when I was finding the inverse, I was just dividing the matrix by 1/9 but in modular arithmetic I actually need to find the multiplicative inverse

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so I ended up with this, which is corret

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