U txhais li cas hauv lub sijhawm sau ntawv?
U txhais li cas hauv lub sijhawm sau ntawv?

Video: U txhais li cas hauv lub sijhawm sau ntawv?

Video: U txhais li cas hauv lub sijhawm sau ntawv?
Video: Hmong song "Daim Ntawv Hauv Lub Fwj'' Dedication to Nalee 2024, Kaum ib hlis
Anonim

Ntawm kab xov tooj nws zoo li no: Thiab interval notation zoo li no: (-∞, 2] U (3, +∞) Peb siv lub " U "to txhais tau tias Union (kev sib koom ua ke ntawm ob pawg). Nco tseg: ceev faj nrog kev tsis sib xws li ntawd.

Dhau li ntawm no, U txhais li cas hauv lej?

Union. ntau Lub teeb ua los ntawm kev sib txuas cov ntsiab lus ntawm ob pawg. Yog li kev sib koom ua ke ntawm A thiab B yog cov ntsiab lus hauv A, lossis B, lossis ob qho tib si. Lub cim yog tshwj xeeb " U "zoo li no: ∪

Ib yam li ntawd, U txhais li cas hauv lub npe? Txawm li cas los xij, qhov tawg hauv lub domain txhais tau tias hais tias peb yuav tsum siv peb lub union cim " u "ntawm peb 2 sau npe daim. Nov yog peb qhov kawg sau npe : (-infinity, 2] u (3, infinity) Nco ntsoov tias infinity yog ib txwm tsis suav nrog thiab " u " txhais tau tias tias ob daim duab ntawm daim duab yog ib feem ntawm qhov ua tau sau npe.

Tom qab ntawd, ib tug kuj yuav nug, dab tsi yog ib qho piv txwv ntawm lub sij hawm notation?

Interval Notation . A sau ntawv rau sawv cev ib lub sijhawm raws li ib khub ntawm tus lej. Cov lej yog qhov kawg ntawm cov lub sijhawm . Cov kab lus thiab / lossis cov kab tuav tau siv los qhia seb cov ntsiab lus xaus puas raug cais lossis suav nrog. Rau piv txwv , [3, 8) ib lub sijhawm ntawm tus lej tiag ntawm 3 thiab 8, suav nrog 3 thiab tsis suav nrog 8.

∩ txhais li cas?

Kev txhais ntawm Kev sib tshuam ntawm Sets: Kev sib tshuam ntawm ob qhov muab teev yog qhov loj tshaj plaws uas muaj tag nrho cov ntsiab lus uas muaj rau ob qho tib si. Lub cim rau denoting kev sib tshuam ntawm sets ' ∩ '.

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