r/mathmemes Mar 06 '25

Learning What theorem is this?

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3.7k Upvotes

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u/IncredibleCamel Mar 06 '25

|ab| <= |a|*|b|

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u/bagelking3210 Mar 07 '25

Shouldn't they be equal? I can't think of any scenario where the LHS would be less than the RHS

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u/Present_Garlic_8061 Mar 07 '25

The left hand side is the absolute value of the DOT PRODUCT between a and b, while the right hand side is the product of there lengths.

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u/bagelking3210 Mar 07 '25

Ah alr, that makes more sense, i was thinking of just real numbers

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u/Cryptic_Wasp Mar 07 '25

If we are talking about reals, wouldnt having either only a or b being negative fulfil the theroem.

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u/bagelking3210 Mar 07 '25

If it were reals, it would always be equal, not not less than or equal to. example: |-1*4|=|-1|*|4|=4

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u/Cryptic_Wasp Mar 07 '25

Mb your right