Kev xam lub kaum sab xis ntawm daim duab peb sab yog ib txoj haujlwm zoo sib xws hauv chav kawm geometry hauv tsev kawm. Txoj hauv kev los daws qhov teeb meem zoo li no nyob ntawm cov xwm txheej paub hauv nws. Lawv tuaj yeem yog cov txiaj ntsig ntawm lwm lub kaum sab xis ntawm daim duab peb sab, sab, lawv cov sine, cosines. Koj yuav tsum tau xyuam xim rau cov duab ntawm daim duab peb sab uas tau piav qhia hauv txoj haujlwm.
Basic rule
Nws tsim nyog nco ntsoov txoj cai yooj yim tshaj plaws rau txhua daim duab peb sab, uas nws yog kev cai pib thaum xam lub kaum sab xis ntawm daim duab peb sab. Nws suab zoo li no: qhov suav ntawm qhov ntsuas ntsuas ntawm txhua lub kaum sab xis ntawm daim duab peb sab yog 180 degrees.
Kev daws
Xaiv lub kaum sab xis ntawm daim duab peb sab yog yooj yim heev. Nyob rau hauv xws li ib tug daim duab peb sab, ib tug ntawm cov ces kaum yog ib txwm sib npaug zos rau 90 degrees, feem, qhov ob ntxiv mus rau tib tus nqi. Yog tias qhov teeb meem twb paub qhov tseem ceeb ntawm ob lub kaum sab xis, ces koj tuaj yeem pom qhov thib peb sai sai los ntawm kev rho tawm cov lej ntawm cov ces kaum paub los ntawm cov lej ntawm cov kaum sab xis ntawm tag nrho daim duab peb sab.
Koj tuaj yeem suav lub kaum sab xis ntawm daim duab peb sab siv lub theorem ntawm sines, cosines, tangents thiab cotangents, paub txog ob ntawm nws sab,Txoj kev no:
- lub tangent ntawm lub kaum sab xis yuav muab sib npaug rau qhov piv ntawm sab nraud rau sab uas nyob ib sab;
- sine - sab nraud rau lub hypotenuse;
- cosine - qhov piv ntawm sab uas nyob ib sab mus rau hypotenuse.
Hauv qhov teeb meem, koj kuj yuav xav tau cov ntaub ntawv ntawm cov bisectors thiab nruab nrab ntawm daim duab peb sab kos los ntawm lub kaum sab xis tsis paub.
Nws yuav tsum nco ntsoov tias qhov nruab nrab yog txoj kab txuas ntawm lub ces kaum thiab nruab nrab ntawm sab nraud. Ib tug bisector yog ib txoj kab uas bisects lub kaum sab xis. Tsis txhob nkim lawv qhov siab thiab vice versa.
Yog hais tias qhov nruab nrab bisects rau sab opposite lub ces kaum, thiab cov ces kaum nyob rau hauv tsis paub daim duab peb sab yog sib npaug, ces lub kaum sab xis no yog 90 degrees.
Yog hais tias lub bisector faib lub kaum sab xis rau ib nrab, thiab dhau li ntawd, peb paub ib lub kaum sab xis ntawm daim duab peb sab thiab lub kaum sab xis ntawm lub hypotenuse thiab lub bisector kos rau nws, ces peb tuaj yeem nrhiav ib nrab ntawm lub kaum sab xis.
Txhua txoj cai no yuav pab koj xam lub kaum sab xis ntawm daim duab peb sab.
