Directrix ntawm daim duab nyob qhov twg?

2024 Tus sau: Fiona Howard | [email protected]. Kawg hloov kho: 2024-01-10 06:38

Tus directrix yog perpendicular rau lub axis ntawm symmetry ntawm parabola thiab tsis kov lub parabola. Yog hais tias lub axis ntawm symmetry ntawm ib tug parabola yog ntsug, lub directrix yog kab rov tav. Yog tias peb xav txog tsuas yog parabolas uas qhib upwards lossis downwards, ces tus directrix yog kab rov tav ntawm daim ntawv y=c.

Koj pom tus directrix li cas?

Yuav ua li cas thiaj nrhiav tau tus directrix, tsom thiab vertex ntawm parabola y=½ x². Lub axis ntawm parabola yog y-axis. Equation of directrix is y=-a. i.e. y=-½ yog qhov sib npaug ntawm directrix.

Koj pom qhov ua kom pom tseeb thiab ncaj qha ntawm daim duab li cas?

Tus qauv qauv yog (x - h) ²=4p (y - k) , qhov ua kom pom tseeb yog (h, k + p) thiab directrix yog y=k - p. Yog hais tias lub parabola yog tig kom nws vertex yog (h, k) thiab nws axis ntawm symmetry yog parallel mus rau lub x-axis, nws muaj ib tug sib npaug ntawm (y - k) ^{2=4p (x - h), qhov tsom xam yog (h + p, k) thiab directrix yog x=h - p.}

Koj pom directrix thiab deb li cas?

Tus directrix yog tus line y=-p Ib qho taw qhia (x, y) ntawm parabola yuav yog qhov deb ntawm qhov tsom mus rau qhov nws yog los ntawm directrix. Ntawd yog, yog tias d₁ yog qhov kev ncua deb ntawm qhov kev tsom mus rau qhov taw tes ntawm parabola, thiab d₂ yog qhov kev ncua deb ntawm cov directrix mus rau qhov taw tes ntawm parabola, ces d₁=d₂

Puas yog directrix sab nraum parabola?

Qhov tsom ntawm parabola ib txwm nyob hauv parabola; lub vertex yeej ib txwm nyob rau ntawm parabola; tus directrix ib txwm nyob sab nraum parabola.