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e(ho0n3
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Homework Statement
Let H and K be subgroups of G of finite index such that [G] and [G:K] are relatively prime. Prove that G = HK.
The attempt at a solution
All I know is that [G intersect K] = [G] [G:K]. What would be nice is if [GK] = [G] [G:K] / [G intersect K], for then I would be done. Anywho, I must somehow show that [GK] = 1 or prove that G = HK directly. Any tips?
Let H and K be subgroups of G of finite index such that [G] and [G:K] are relatively prime. Prove that G = HK.
The attempt at a solution
All I know is that [G intersect K] = [G] [G:K]. What would be nice is if [GK] = [G] [G:K] / [G intersect K], for then I would be done. Anywho, I must somehow show that [GK] = 1 or prove that G = HK directly. Any tips?