Kev txhais ntawm daim iav Convex
Ib hom iav uas siv hauv lub neej txhua hnub yog daim iav convex. Daim iav convex yog daim iav uas muaj cov duab nkhaus, qhov twg qhov chaw ntawm daim iav uas cuam tshuam lub teeb nkhaus mus rau pem hauv ntej.
Siv
Yog tias koj tau pom daim iav saib tom qab ntawm lub tsheb kauj vab lossis lub tsheb, tej zaum koj yuav paub txog kev siv daim iav convex txhua hnub. Lawv siv ua daim iav saib tom qab vim tias cov duab uas lawv tsim tawm me dua, ua rau pom tau dav dua. Dhau li ntawm qhov loj me ntawm cov duab, txhua daim duab uas tsim tawm yog virtual lossis imaginary. Thov kawm txog lub ncauj lus. daim iav convex duab kom koj nkag siab meej.
Qhov Chaw Tseem Ceeb
Yog tias qhov chaw ntawm daim iav uas cuam tshuam lub teeb ntsib ib yam khoom nyob deb heev, xws li lub hnub, ces lub teeb uas lub hnub tso tawm yuav sib luag rau lub axis tseem ceeb ntawm daim iav, raws li pom hauv daim duab hauv qab no. Lub axis tseem ceeb yog ib txoj kab xav uas perpendicular rau qhov chaw nruab nrab ntawm daim iav.
Thaum ntaus rau ntawm daim iav, txhua lub teeb lossis lub teeb ntawm lub teeb ua raws li txoj cai ntawm kev cuam tshuam ntawm lub teeb. Tag nrho cov teeb ci ntsa iab zoo li los ntawm qhov chaw tseem ceeb ntawm daim iav convex (F). Hauv lwm lo lus, qhov chaw tseem ceeb yog qhov chaw duab ntawm ib yam khoom uas nyob deb heev ntawm qhov chaw ntawm daim iav thiab daim duab no yog virtual.
Qhov Ntev Focal
Qhov ntev focal (f) yog qhov deb ntawm qhov chaw focal (F) thiab qhov chaw ntawm daim iav. Qhov C yog qhov chaw nruab nrab ntawm qhov nkhaus ntawm daim iav. Qhov ntev focal ntawm daim iav yog f (qhov ntev focal = f = FQ) thiab qhov radius ntawm curvature ntawm daim iav yog r (radius ntawm curvature = r = CQ = CP).
Cov kab teeb ci ntsa iab ntaus rau ntawm daim iav ntawm P thiab tom qab ntawd raug cuam tshuam los ntawm daim iav, qhov twg cov kab teeb ci ntsa iab zoo li los ntawm qhov chaw tseem ceeb F. Cov kab dotted CP yog kab ib txwm. Lub teeb ci ntsa iab thiab lub teeb ci ntsa iab ua raws li txoj cai ntawm kev cuam tshuam ntawm lub teeb uas lub kaum sab xis (θ) sib npaug rau lub kaum sab xis ntawm kev cuam tshuam (θ) thiab lub kaum sab xis no sib npaug rau lub kaum sab xis ntawm daim duab peb ceg PCQ (θ). Lub kaum sab xis ntawm daim duab peb ceg PCQ sib npaug rau lub kaum sab xis ntawm daim duab peb ceg CPF yog li daim duab peb ceg PFC yog daim duab peb ceg sib npaug. Vim tias daim duab peb ceg PFC yog daim duab peb ceg sib npaug ces qhov ntev ntawm PF sib npaug rau qhov ntev ntawm CF. Los ntawm kev xav tias qhov dav ntawm daim iav me dua lub vojvoog ntawm qhov nkhaus ntawm daim iav convex yog li qhov ntev ntawm PF raug suav tias sib npaug rau qhov ntev ntawm FQ. Vim tias CF = PF thiab PF = FQ ces CQ = 2 CF = 2 FQ. CQ = r = lub vojvoog ntawm qhov nkhaus ntawm daim iav thiab FQ = f = qhov ntev ntawm lub iav. Yog li nws tuaj yeem xaus lus tias lub vojvoog ntawm qhov nkhaus ntawm daim iav (r) = 2 x qhov ntev ntawm lub iav (f). Kev suav lej:
r = 2 f los yog f = r / 2
Duab ntxoov ntxoo
Cov iav concave tuaj yeem tsim cov duab tiag tiag thiab virtual, thaum cov iav convex tsuas yog tuaj yeem tsim cov duab virtual. Kev tsim cov duab ntawm ib yam khoom los ntawm daim iav convex tau piav qhia meej hauv cov ncauj lus. daim iav convex duab.
Maya tus duab ntxoov ntxoo
Thaum lub teeb ci ntsa iab los rau ntawm daim iav, qhov kev taw qhia ntawm lub teeb ci ntsa iab zoo li los ntawm qhov chaw tseem ceeb ntawm daim iav thiab qhov chaw nruab nrab ntawm daim iav qhov nkhaus. Vim tias lub teeb tsis dhau mus tom qab daim iav, daim duab tsim yog duab ntxoov ntxoo virtual los yog dab phemYog koj muab lub vijtsam tso rau hauv qhov chaw uas daim duab virtual nyob, yuav tsis muaj duab ntxoov ntxoo tshwm sim ntawm lub vijtsam.
