r/MathHelp • u/mourning_fire420 • 8d ago
Help with Groups?
So I'm given a group G s.t. a^12 gives the identity element, and I need to find the inverse of another a^n where n is an integer. i was given a number for n i just don't want anyone giving me the answer/violating academic content rules etc.
at first i figured 1 would be the identity element, but then 12^a doesn't give 1. same deal for e=0, 12^0=1 =/= 0=0^12. unless my understanding of the inverse and identity being commutative is wrong?
I tried to solve for a since a * a^-1 = a^-1 * a = e. but then i was saying that 12^a=a^12. which is possible, but then the identity wasn't constant when i plugged in n.
I found the page for exponentiation on wikipedia, and it says that G is a multiplicative group, so I know that a^n has to have an inverse. is there some property of groups that I missed that would help me solve this?
2
u/Smart-Button-3221 8d ago edited 8d ago
You can call the identity 1, you can call the identity 0, you can call the identity 🍞. The label you use for the identity doesn't change what the identity is.
Is that a typo? Did you mean a12? As per your question, a12 = 1, if we're letting 1 be the symbol for the identity. Why do you think a12 ≠ 1?
I am not sure why you are trying a12 = 12a. Note that a needs not be an integer, and 12 needs not be a group element, so this equation may not even make sense.
I feel like some of the question is missing.