Injective txhais li cas?
Injective txhais li cas?

Video: Injective txhais li cas?

Video: Injective txhais li cas?
Video: [New] Tactical Glock Blowback Shell Ejecting Pistol - Toy Gun 2024, Kaum ib hlis
Anonim

Hauv lej, ib txhaj tshuaj muaj nuj nqi (tseem hu ua kev txhaj tshuaj, lossis ib-rau-ib txoj haujlwm) yog ib txoj haujlwm uas qhia cov ntsiab lus ntawm nws lub npe rau cov ntsiab lus ntawm nws cov codomain. Hauv lwm lo lus, txhua lub ntsiab lus ntawm lub luag haujlwm lub codomainis cov duab ntawm feem ntau ntawm nws lub npe.

Ib yam li ntawd, koj tuaj yeem nug, qhov piv txwv ntawm Kev Txhaj Tshuaj yog dab tsi?

Piv txwv : Cov muaj nuj nqi f(x) = x2los ntawm cov txheej txheem ntawm cov lej tiag tiag rau cov lej tiag tiag yog ob qho tib si txhaj tshuaj thiab surjective. Yog li nws kuj yog bijective . Tab sis tib yam muaj nuj nqi los ntawm cov txheej txheem ntawm tag nrho cov lej tsis yog bijective vim peb tuaj yeem muaj, rau piv txwv , ob leeg.

Tsis tas li ntawd, koj ua pov thawj li cas Surjective thiab Injective? vim f yog ib tug bijection. Rau ua pov thawj muaj nuj nqi isbijective, koj yuav tsum ua pov thawj tias yog txhaj tshuaj thiab thiab qhov tseeb . " Txhaj tshuaj " txhais tau tias tsis muaj ob lub ntsiab lus nyob rau hauv lub ntsiab ntawm lub luag haujlwm tau mapped rau tib daim duab." Qhov tseeb " txhais tau hais tias txhua yam hauv qhov ntau ntawm cov haujlwm raug ntaus los ntawm kev ua haujlwm.

Raws li, yog qhov khoob muaj nuj nqi Injective?

Raws li cov ntsiab lus no, ib qho tsis muaj nuj nqi tsis yog txhaj tshuaj vim ˘f:S→∅ tsis yog ib muaj nuj nqi.

Yuav ua li cas koj paub yog hais tias muaj nuj nqi yog graphically?

Rau ib-ib qho: tsuas yog cov kab kos duab (perpendicular rau x-axis) ces yog tias koj pom cov kab sib tshuam ntawm qhov nkhaus ntawm muaj nuj nqi tiam no tsis yog ib leeg. Raws li rau ib-ib qho kab ntsug yuav tsum sib tshuam nrog daim duab ntawm muaj nuj nqi ntawm ib qho!

Pom zoo: