Kev tshawb fawb ntawm geometry qhia peb tias daim duab peb sab, square, lub voos xwmfab yog dab tsi. Hauv lub ntiaj teb niaj hnub no, nws tau kawm hauv tsev kawm los ntawm txhua tus neeg yam tsis muaj kev zam. Tsis tas li ntawd, ib qho kev tshawb fawb uas ncaj qha kawm seb daim duab peb sab yog dab tsi thiab nws muaj dab tsi yog trigonometry. Nws tshawb txog txhua yam tshwm sim cuam tshuam nrog cov duab geometric. Peb yuav tham txog dab tsi daim duab peb sab hnub no hauv peb tsab xov xwm. Lawv hom yuav tau piav qhia hauv qab no, nrog rau qee qhov theorems ntsig txog lawv.
Dab tsi yog daim duab peb sab? Txhais
Nov yog ib lub tiaj tiaj. Nws muaj peb lub ces kaum, uas yog qhov tseeb ntawm nws lub npe. Nws kuj muaj peb sab thiab peb vertices, thawj ntawm uas yog ntu, qhov thib ob yog cov ntsiab lus. Paub tias ob lub ces kaum sib npaug li cas, koj tuaj yeem pom qhov thib peb los ntawm kev rho tawm cov lej ntawm thawj ob ntawm tus lej 180.
Dab tsi yog daim duab peb sab?
Lawv tuaj yeem faib raws li ntau yam qauv.
Ua ntej ntawm tag nrho cov, lawv muab faib ua acute-angled, obtuse-angled thiab rectangular. Thawj muaj cov kaum sab xis, uas yog, cov uas qis dua 90 degrees. Hauv obtuse-angled sawv daws yuav, ib qho ntawm cov ces kaum yog obtuse, uas yog, xws liuas yog sib npaug rau ntau tshaj 90 degrees, lwm ob yog mob. Acute triangles kuj muaj xws li daim duab peb sab sib npaug. Xws li daim duab peb sab muaj txhua sab thiab kaum sib npaug. Lawv txhua tus sib npaug li 60 degrees, qhov no tuaj yeem suav tau yooj yim los ntawm kev faib cov lej ntawm tag nrho cov ces kaum (180) los ntawm peb.
daim duab peb sab
Nws tsis tuaj yeem hais tsis tau hais txog dab tsi daim duab peb sab yog.
Daim duab no muaj ib lub kaum sab xis sib npaug li 90 degrees (ncaj), uas yog, ob sab ntawm nws yog perpendicular. Lwm ob lub kaum sab xis yog mob. Lawv tuaj yeem sib npaug, ces nws yuav yog isosceles. Lub Pythagorean theorem muaj feem xyuam rau txoj cai daim duab peb sab. Nrog nws cov kev pab, koj tuaj yeem nrhiav qhov thib peb, paub txog thawj ob. Raws li qhov kev xav no, yog tias koj ntxiv cov xwmfab ntawm ib ceg mus rau lub xwmfab ntawm lwm qhov, koj tuaj yeem tau txais lub square ntawm hypotenuse. Lub xwmfab ntawm ceg tuaj yeem suav tau los ntawm kev rho tawm cov xwmfab ntawm cov ceg uas paub los ntawm cov square ntawm hypotenuse. Hais txog dab tsi daim duab peb sab yog, peb tuaj yeem nco qab cov isosceles. Qhov no yog ib qho uas ob sab sib npaug, thiab ob lub ces kaum kuj sib npaug.
txhais ceg thiab hypotenuse yog dab tsi?
Lub ceg yog ib sab ntawm daim duab peb sab uas tsim lub kaum sab xis ntawm 90 degrees. Lub hypotenuse yog qhov seem uas yog opposite lub kaum sab xis. Los ntawm nws, ib qho perpendicular tuaj yeem txo qis rau ntawm txhais ceg. Qhov piv ntawm cov ceg uas nyob ib sab mus rau lub hypotenuse yog hu ua cosine, thiab qhov opposite yog hu ua sine.
daim duab peb sab Egypt - nws yog dab tsi?
Nws yog duab plaub. Nws ob txhais ceg yog sib npaug rau peb thiab plaub, thiablub hypotenuse yog tsib. Yog tias koj pom tias ob txhais ceg ntawm daim duab peb sab no sib npaug rau peb thiab plaub, koj tuaj yeem paub tseeb tias lub hypotenuse yuav sib npaug rau tsib. Tsis tas li ntawd, raws li txoj cai no, nws tuaj yeem txiav txim siab tau yooj yim tias txhais ceg yuav sib npaug peb yog tias qhov thib ob yog sib npaug rau plaub, thiab hypotenuse yog tsib. Txhawm rau ua pov thawj cov lus no, koj tuaj yeem siv Pythagorean theorem. Yog tias ob txhais ceg yog 3 thiab 4, ces 9 + 16 \u003d 25, lub hauv paus ntawm 25 yog 5, uas yog, lub hypotenuse yog 5. Tsis tas li ntawd, ib daim duab peb sab Egyptian hu ua ib daim duab peb sab, uas nws sab yog 6, 8 thiab 10.; 9, 12 thiab 15 thiab lwm tus lej nrog qhov sib piv ntawm 3: 4: 5.
Dab tsi ntxiv yuav yog daim duab peb sab?
Daim duab peb sab kuj tuaj yeem sau thiab kos. Daim duab nyob ib ncig ntawm lub voj voog tau piav qhia yog hu ua inscribed, tag nrho nws cov vertices yog cov ntsiab lus dag ntawm lub voj voog. Ib daim duab peb sab circumscribed yog ib lub voj voog yog inscribed. Tag nrho nws cov sab tau ntsib nrog nws ntawm qee lub ntsiab lus.
thaj tsam ntawm daim duab peb sab nyob li cas?
Qhov cheeb tsam ntawm ib daim duab yog ntsuas hauv square units (square meters, square millimeters, square centimeters, square decimeters, thiab lwm yam.) Cov nqi no tuaj yeem suav nrog ntau txoj hauv kev, nyob ntawm seb hom daim duab peb sab. Cov cheeb tsam ntawm ib daim duab nrog cov ces kaum tuaj yeem pom los ntawm kev muab nws sab los ntawm qhov perpendicular poob rau nws los ntawm lub kaum sab xis, thiab faib cov duab no los ntawm ob. Koj tseem tuaj yeem nrhiav tau tus nqi no los ntawm kev sib npaug ntawm ob sab. Tom qab ntawd muab tus lej no los ntawm sine ntawm lub kaum sab xis ntawm ob sab, thiab faib qhov no los ntawm ob. Paubtxhua sab ntawm ib daim duab peb sab, tab sis tsis paub nws cov ces kaum, koj tuaj yeem pom thaj tsam ntawm lwm txoj kev. Ua li no, koj yuav tsum nrhiav ib nrab ntawm ib puag ncig. Tom qab ntawd hloov pauv qhov sib txawv ntawm tus lej no thiab muab cov plaub qhov txiaj ntsig tau txais. Tom ntej no, nrhiav lub hauv paus square ntawm tus lej uas tuaj tawm. Lub cheeb tsam ntawm daim duab peb sab inscribed tuaj yeem pom los ntawm kev muab faib rau txhua sab thiab faib cov lej uas tshwm sim los ntawm lub vojvoog ntawm lub voj voog uas nyob ib puag ncig nws, muab faib ua plaub.
Thaj chaw ntawm daim duab peb sab circumscribed pom nyob rau hauv no txoj kev: muab ib nrab ntawm lub perimeter los ntawm lub vojvoog ntawm lub voj voog uas tau sau nyob rau hauv nws. Yog tias daim duab peb sab sib npaug, ces nws thaj chaw tuaj yeem pom raws li hauv qab no: peb square rau sab, muab cov txiaj ntsig tau los ntawm lub hauv paus ntawm peb, ces faib cov lej no los ntawm plaub. Ib yam li ntawd, koj tuaj yeem xam qhov siab ntawm daim duab peb sab uas txhua sab sib npaug, rau qhov no koj yuav tsum muab ib qho ntawm lawv los ntawm cov hauv paus ntawm peb, thiab muab cov lej no los ntawm ob.
Daim duab peb sab ntsig txog theorems
Cov theorems tseem ceeb uas cuam tshuam nrog daim duab no yog Pythagorean theorem tau piav qhia saum toj no, sine thiab cosine theorems. Qhov thib ob (sine) yog tias yog tias koj faib ib sab los ntawm sine ntawm lub kaum sab xis ntawm nws, koj tuaj yeem tau txais lub vojvoog ntawm lub voj voog uas tau piav qhia nyob ib puag ncig nws, muab faib los ntawm ob. Qhov thib peb (cosine) yog tias yog cov lej ntawm cov squares ntawm ob sab rho tawm lawv cov khoom, muab faib los ntawm ob thiab cov cosine ntawm lub kaum sab xis nyob nruab nrab ntawm lawv, ces koj tau txais cov square ntawm peb sab.
Dali Daim duab peb sab - nws yog dab tsi?
Ntau, ntsib nrog lub tswv yim no, thaum xub thawj xav tias qhov no yog qee yam kev txhais hauv geometry, tab sis qhov no tsis yog txhua yam. Lub Dali Daim duab peb sab yog lub npe nrov rau peb qhov chaw uas zoo sib xws nrog lub neej ntawm tus kws kos duab nto moo. Nws "sab saum toj" yog lub tsev uas Salvador Dali nyob, lub tsev fuabtais uas nws muab rau nws tus poj niam, thiab lub tsev khaws puav pheej ntawm surrealistic paintings. Thaum mus ncig ntawm cov chaw no, koj tuaj yeem kawm paub ntau qhov tseeb txog qhov tshwj xeeb muaj tswv yim no, paub thoob plaws ntiaj teb.
