geometry yog ib qho kev tshawb fawb zoo heev uas tau qhia hauv cov tsev kawm ntawv Lavxias hauv qib xya. Tab sis qee zaum cov ntsiab lus uas tau hais hauv zaj lus qhia tsis meej, thiab sim nyeem ib nqe lus hauv phau ntawv nyeem tsuas yog ua rau qhov xwm txheej hnyav dua. Tom qab ntawd lub omniscient Internet los cawm, los yog qee cov tub ntxhais kawm tsuas yog qhib cov ntawv npaj ua tom tsev, uas yog qhov tsis ncaj ncees lawm, vim tias cov lus nug tseem tsis tau teb, lub hlwb tsis txhim kho, muaj teeb meem ntau ntxiv nrog rau kev nkag siab ntawm cov ntaub ntawv hauv cov lus nug. zaj lus qhia, uas ua rau cov qhab nia tsis zoo. Hauv tsab xov xwm no, peb yuav txheeb xyuas ib qho ntawm cov ntsiab lus tseem ceeb, nrog kev pab los ntawm ntau txoj haujlwm tau daws. Dab tsi yog qhov txhais ntawm qhov siab ntawm daim duab peb sab? Yuav tsim li cas? Koj yuav pom cov lus teb rau cov lus nug no thiab ntau lwm cov lus nug hauv kab lus no.
Kev txiav txim siab qhov siab ntawm daim duab peb sab
Kev nkag siab lub ntsiab lus ntawm lub ntsiab lus, thiab vim li cas nws thiaj li xav tau, ib txwm pib nrog kev kawm txog kev xav. Yog li, qhov siab ntawm daim duab peb sab yog ib qho perpendicular poob los ntawm lub vertex ntawm daim duab peb sab mus rau kab uas muaj qhov opposite sab. Vim li cas ho tsis nyob ntawm sab? Peb yuav daws qhov no me ntsis tom qab.
Ntau npaum li ua taukos qhov siab hauv daim duab peb sab? Tus naj npawb ntawm qhov siab yog tib yam li tus naj npawb ntawm vertices, uas yog, peb. Tag nrho peb qhov kev sib tshuam ntawm daim duab peb sab lub perpendiculars sib tshuam ntawm ib qho taw tes.
Cia peb rov hais dua qhov kev xav txog ob yam tseem ceeb - bisector thiab nruab nrab.
Bisector - ib txoj kab hluav taws xob txuas lub vertex ntawm daim duab peb sab nrog rau sab nraud, thaum faib lub kaum sab xis rau hauv ob qhov sib npaug.
Median yog ib ntu txuas lub vertex ntawm lub kaum sab xis nrog rau nruab nrab ntawm sab nraud.
Timpeb daim duab peb sab
Muaj ntau ntau yam ntawm daim duab peb sab hauv geometry, nyob rau hauv txhua tus ntawm lawv qhov siab ua lawv lub luag haujlwm. Cia peb saib txhua hom ntawm daim duab no kom ntxaws. Kev txiav txim siab qhov siab ntawm daim duab peb sab yuav pab peb nrog qhov no.
Cia peb pib nrog ib qho yooj yim acute-angled scalene daim duab peb sab, nyob rau hauv uas txhua lub ces kaum yog mob thiab tsis sib npaug li 60 degrees, thiab ob sab tsis sib npaug. Hauv daim duab geometric no, qhov siab yuav sib tshuam, tab sis qhov taw tes no yuav tsis yog qhov nruab nrab ntawm daim duab peb sab.
Hauv daim duab peb sab obtuse, qhov ntsuas ntawm ib lub kaum sab xis yog siab dua 90 degrees. Qhov siab tawm ntawm lub kaum sab xis yog qis dua mus rau txoj kab ncaj nraim uas muaj sab nraud.
Tom ntej no yog daim duab peb sab isosceles. Nws tsuas muaj ob sab thiab ob lub kaum sab xis ntawm lub hauv paus. Interestingly, qhov siab kos los ntawm vertex mus rau lub hauv paus ntawm daim duab peb sab coincides nrog nruab nrab thiab bisector.
Hauv ib daim duab peb sab sib npaug, txhua sab thiab cov ces kaum uas sib npaug li 60 degrees (txhua tus) sib npaug. Txhua qhov siab, nruab nrab thiabcov bisectors coincide thiab sib tshuam ntawm ib qho chaw - qhov nruab nrab ntawm daim duab peb sab.
qauv ntsuas qhov siab ntsig txog
Rau txhua qhov xwm txheej saum toj no, muaj cov qauv txiav txim siab qhov siab, tab sis hauv kab lus no peb yuav txiav txim siab tsuas yog cov uas tsim nyog rau txhua hom duab peb sab. Muaj plaub yam qauv no.
- Qhov yooj yim tshaj plaws thiab pheej yig tshaj: H=2S / a. Paub thaj tsam thiab qhov ntev ntawm sab uas yog kos, peb tuaj yeem pom qhov siab los ntawm kev faib ob qhov khoom ntawm thaj tsam ntawm sab.
- Yog tias daim duab peb sab nyob hauv ib lub voj voog, ces muaj ib qho qauv rau rooj plaub no: H=bc/2R. Txhawm rau nrhiav qhov siab, koj yuav tsum tau faib cov sab uas lub perpendicular tsis poob los ntawm ob qhov khoom ntawm lub vojvoog ntawm lub voj voog ncig ncig daim duab peb sab.
- Paub tsuas yog ob sab, peb kuj tuaj yeem pom qhov siab: H=(2√(p(p-a)(p-b)(p-c)))/a, qhov twg: p yog ib nrab-ib puag ncig; a - sab ntawm qhov siab qis; b, c - sab ntawm lub perpendicular tsis poob.
- Thiab rau cov uas twb pib kawm trigonometry thiab paub tias sine thiab cosine yog dab tsi, muaj cov qauv no: H=bsinY=csinB. Sine - qhov sib piv ntawm qhov opposite sab mus rau lub perpendicular; H - perpendicular; b thiab c yog ob sab opposite lub kaum sab xis Y thiab B, raws.
daim duab peb sab
Tej zaum koj yuav xav tias peb tsis nco qab txog cov duab peb sab, tab sis peb tsis tau. Ib daim duab peb sab yog ib daim duab peb sab uas ib lub kaum sab xis yog 90 degrees. Tsuas muaj ib qhov siab nyob rau hauv ib daim duab peb sab, vim yog ob qho tib sisab, los yog ob txhais ceg. Qhov tsuas yog perpendicular yoojyim lub kaum sab xis thiab nqis mus rau lub hypotenuse. Muaj ntau ntau cov qauv los nrhiav rau rooj plaub no:
- H=ab/c;
- H=ab/√(a2 +b 2);
- H=csinAcosA=c sinBcosB;
- H=bsinA=a sinB;
- H=√de.
qhov twg:
H - qhov siab;
a, b – ceg;
c – hypotenuse;
A, B - kaum sab xis ntawm lub hypotenuse;
d, e - ntu tau los ntawm kev faib cov hypotenuse los ntawm qhov siab.
Zoo kawg
Yog li, hauv kab lus no peb tau txiav txim siab lub ntsiab lus ntawm qhov siab ntawm daim duab peb sab. Dab tsi yog hom ntawm daim duab peb sab? Cov qauv twg tuaj yeem siv los nrhiav qhov siab? Tam sim no koj tuaj yeem muab cov ncauj lus kom ntxaws, thiab qhov tseem ceeb tshaj, cov lus teb kom raug rau tag nrho cov lus nug no.
