I need to solve this question
Favorites|Homepage
Subscriptions | sitemap
HOME > > I need to solve this question

I need to solve this question

[From: ] [author: ] [Date: 12-04-03] [Hit: ]
48 - (- 6.d = 6.48 + 6.The distance is 13 units.......
A parabola with a vertical axis has its vertex at the origin and passes through point (7, 7). the parabola intersects line y=6 at two points. the length of the segment joining these points is: 14, 13, 12, 8.6, 6.5 .
answer is 14. but i don't understand how it was solved so please try to explain how it solves.

-
Vertex (0, 0):

h = 0
k = 0

Point (7, 7):

x = 7
y = 7

y = a(x - h)² + k:

7 = a(7 - 0)² + 0
7 = a(7)²
7 = a(49)
7 = 49a
a = 7 / 49
a = 1/7

Equation of Parabola:

y = 1/7 x²

Equation of Line:

y = 6

Point of Intersection: y = y, so

1/7 x² = 6
x² = 6 / (1/7)
x² = 6(7)
x² = 42
x = √42
x = ± 6.48

x1 = 6.48
x2 = - 6.48

Distance = d:

d = x1 - x2
d = 6.48 - (- 6.48)
d = 6.48 + 6.48
d ≈ 13

The distance is 13 units.
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
 
1
keywords: solve,to,need,this,question,I need to solve this question
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .