Completing the Square: Solving Quadratic Equations
第1页/共1页
Completing the Square: Solving Quadratic Equations
Some quadratics are fairly simple to solve because they are of the form "something-with-x squared equals some number", and then you take the square root of both sides. An example would be:
(x – 4)2 = 5
x – 4 = ± sqrt(5)
x = 4 ± sqrt(5)
x = 4 – sqrt(5) and x = 4 + sqrt(5)
Unfortunately, most quadratics don't come neatly squared like this. For your average everyday quadratic, you first have to use the technique of "completing the square" to rearrange the quadratic into the neat "(squared part) equals (a number)" format demonstrated above. For example:
* Find the x-intercepts of y = 4x2 – 2x – 5.
To solve, refer to this site:
http://www.purplemath.com/modules/sqrquad.htm
(x – 4)2 = 5
x – 4 = ± sqrt(5)
x = 4 ± sqrt(5)
x = 4 – sqrt(5) and x = 4 + sqrt(5)
Unfortunately, most quadratics don't come neatly squared like this. For your average everyday quadratic, you first have to use the technique of "completing the square" to rearrange the quadratic into the neat "(squared part) equals (a number)" format demonstrated above. For example:
* Find the x-intercepts of y = 4x2 – 2x – 5.
To solve, refer to this site:
http://www.purplemath.com/modules/sqrquad.htm
lonelytree- 帖子数 : 128
248
注册日期 : 09-07-29
第1页/共1页
您在这个论坛的权限:
您不能在这个论坛回复主题