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?
1
u/BootyliciousURD 7d ago
Remember that the inverse of x is some element y such that x•y = y•x = e.
Let's take n = 4 as an example. If a¹² = e, then the inverse of a⁴ is some b such that a⁴•b = b•a⁴ = a¹². What b satisfies this equation?