Peb txhua tus tau siv sijhawm ntau teev los daws qhov teeb meem geometry. Tau kawg, cov lus nug tshwm sim, vim li cas koj thiaj yuav tsum kawm lej txhua? Cov lus nug yog tshwj xeeb tshaj yog muaj feem xyuam rau geometry, kev paub txog uas, yog tias muaj txiaj ntsig, yog tsawg heev. Tab sis kev lej muaj lub hom phiaj rau cov uas tsis mus ua cov neeg ua haujlwm hauv kev tshawb fawb tiag tiag. Nws ua rau tib neeg ua haujlwm thiab txhim kho.
Lub hom phiaj tseem ceeb ntawm kev ua lej tsis yog los qhia cov tub ntxhais kawm paub txog kev kawm. Cov xib fwb tau teem lawv tus kheej lub hom phiaj ntawm kev qhia cov me nyuam xav, xav, xav, tsom xam thiab sib cav. Qhov no yog qhov peb pom hauv geometry nrog nws ntau axioms thiab theorems, corollaries thiab proofs.
Cosine theorem
Ib txhij nrog trigonometric functions thiab tsis sib xws, algebra pib kawm cov ces kaum, lawv lub ntsiab lus thiab nrhiav. Lub theorem cosine yog ib qho ntawm thawj cov qauv uas txuas ob sab ntawm kev kawm lej hauv kev nkag siab ntawm cov tub ntxhais kawm.
txhawm rau nrhiav ib sab los ntawm ob qho tib si thiab lub kaum sab xis ntawm lawv, siv cosine theorem. Rau ib daim duab peb sab nrog lub kaum sab xis, Pythagorean theorem kuj tsim nyog rau peb, tab sis yog tias peb tham txog ib qho kev txiav txim siab,ces nws siv tsis tau ntawm no.
Lub theorem cosine zoo li no:
AC 2=AB 2+ BC 2- 2 AB BC cos<ABS
Lub square ntawm ib sab yog sib npaug rau cov lej ntawm ob sab squared, rho tawm lawv cov khoom ua ob zaug thiab cov cosine ntawm lub kaum lawv tsim.
Yog tias koj saib ze dua, cov qauv no zoo ib yam li Pythagorean theorem. Tseeb tiag, yog tias peb coj lub kaum sab xis ntawm ob txhais ceg sib npaug li 90, ces tus nqi ntawm nws cov cosine yuav yog 0. Yog li ntawd, tsuas yog cov lej ntawm cov squares ntawm ob sab yuav nyob twj ywm, uas qhia txog Pythagorean theorem.
Cosine Theorem: Pov Thawj
Los ntawm cov lus no peb txiav cov qauv AC 2thiab tau:
AC 2 =SU 2 + AB 2 - 2ABBCcos <ABC
Yog li, peb pom tias cov lus hais sib haum rau cov qauv saum toj no, uas qhia nws qhov tseeb. Peb tuaj yeem hais tias lub theorem cosine tau raug pov thawj. Nws yog siv rau txhua yam ntawm daim duab peb sab.
Siv
Ntxiv rau cov lus qhia hauv lej thiab physics, qhov theorem no tau siv dav hauv kev tsim vaj tsev thiab kev tsim kho, suav cov sab thiab cov ces kaum. Nrog nws cov kev pab, txiav txim siab qhov ntev ntawm lub tsev thiab cov khoom siv uas yuav tsum tau ua rau nws qhov kev tsim kho. Tau kawg, feem ntau ntawm cov txheej txheem uas yav tas los yuav tsum tau ncaj qha tib neeg kev koom tes thiab kev paub,automated hnub no. Muaj ntau ntau cov kev pab cuam uas tso cai rau koj simulate tej yaam num ntawm lub computer. Lawv qhov kev zov me nyuam kuj tau ua tiav los ntawm txhua txoj cai lej, cov khoom thiab cov qauv.
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