香港特色

標題:

equations of circle

發問:

• 法國酒店,LV店退稅一問和去迪士尼方法
• 請問有冇人係法國巨星影個婚紗相
• 幾條考試的數學問題...@1@

此文章來自奇摩知識+如有不便請留言告知

A circle C with centre P(2,0) cuts the line L: y=x at two distinct points Q and R and QR=2ai) Find the distance of P to the line L ii) Find the radius of the circle C iii) Find the equation of circle Cbi) Find the equation od the family of ciclrs passing through Q and R ii) Find the equation of the... 顯示更多 A circle C with centre P(2,0) cuts the line L: y=x at two distinct points Q and R and QR=2 ai) Find the distance of P to the line L ii) Find the radius of the circle C iii) Find the equation of circle C bi) Find the equation od the family of ciclrs passing through Q and R ii) Find the equation of the circle C' passing through P,Q and R c) Show that the tangent to the circle C' at P is parallel to QR.

最佳解答:

a i) Find the distance of P to the line L Ans: Distance = abs(0-2)/(1^2+1^2)^0.5)=(2)^0.5// ii) Find the radius of the circle C Ans: (QR/2)^2+(distance of P to the line L)^2=radius^2 1^2+2=radius^2 radius=(3)^0.5// iii) Find the equation of circle C Ans: (x-2)^2+(y-0)^2=3 x^2+y^2-4x+1=0// b i) Find the equation do the family of circles passing through Q and R the equation do the family of circles passing through Q and R is (x^2+y^2-4x+1)+k(x-y)=0 x^2+y^2+(k-4)x-y+1=0// ii) Find the equation of the circle C' passing through P,Q and R Ans: sub P(2.0) into x^2+y^2+(k-4)x-y+1=0// 2^2+0^2+(k-4)2-0+1=0 k=5/2// so the the equation of the circle C' passing through P,Q and R is x^2+y^2+(3/2)x-y+1=0// c) Show that the tangent to the circle C' at P is parallel to QR. x^2+y^2+(3/2)x-y+1=0 2x+2y(dy/dx)+(3/2)-(dy/dx)=0 dy/dx=(4x+3)/(2-4y) the sloer of tangent to the circle C' at P=(4(2)+3)/(2-4(0)=11/2,

其他解答: