Please answer this fast. Today is exam.
Find the focal distance of a point on the parabola y²=20x if the abscissa of the point be 7.
Answers
◆【Solution】◆
As we know the figure drawn by the moving particle such that distance of particle with the fixed line (Directrix) is equal to the distance with the fixed point (Focus) is Parabola.
The distance of a point on parabola from focus is known as focal distance of the Point.
x = 7
y² = 20x
y² = 20(7)
y² = 140
y = √140
Point on parabola = (7,√140)
For parabola y² = 4ax Directrix is X = a
For parabola y²= 20x Directrix is X = 5
Distance from focus = Distance from Directrix
Focal distance = | 7 - 5 |
◆【Focal distance = 2 units】◆
Sorry for late answer
Answer:
As we know the figure drawn by the moving particle such that distance of particle with the fixed line (Directrix) is equal to the distance with the fixed point (Focus) is Parabola.
The distance of a point on parabola from focus is known as focal distance of the Point.
x = 7
y² = 20x
y² = 20(7)
y² = 140
y = √140
Point on parabola = (7,√140)
For parabola y² = 4ax Directrix is X = a
For parabola y²= 20x Directrix is X = 5
Distance from focus = Distance from Directrix
Focal distance = | 7 - 5 |
◆【Focal distance = 2 units】◆
Distance of a point (m,d) from line ax + by + c
can be written as (| am + bd + c )