Stuck with a C1 maths question
Favorites|Homepage
Subscriptions | sitemap
HOME > > Stuck with a C1 maths question

Stuck with a C1 maths question

[From: ] [author: ] [Date: 12-01-01] [Hit: ]
find the range of possible values of k.Thanks-Since L and C do not intersect,has no real solution.The equation must have no real solution.As the range of 3x^2 - 6x + 7 is [4,∞),......
Please could someone point me in the right direction with this question..

The curve C has equation y = 3x² - 4x + 7. The line L has equation y = 2x + k, where k is a constant.
Given that L and C do not intersect, find the range of possible values of k.


Thanks

-
Since L and C do not intersect, the equation

3x² - 4x + 7 = 2x + k

has no real solution.

You can rewrite the equation as

3x² - 6x + 7-k = 0

The equation must have no real solution. This means that the discriminant must be negative:

(-6)² - 4*(3)*(7-k) <0

==>36 - 84 +12k < 0

==>12k< 48

==> k< 4

-
3x^2 - 4x + 7 ≠ 2x + k
3x^2 - 6x + 7 ≠ k
As the range of 3x^2 - 6x + 7 is [4,∞), we have k < 4.
1
keywords: maths,Stuck,with,question,Stuck with a C1 maths question
New
Hot
© 2008-2010 http://www.science-mathematics.com . Program by zplan cms. Theme by wukong .